#include <bits/stdc++.h>
#define FOR(i, a, b)    for(int i = a; i <= b; i++)
#define REP(i, a, b)    for(int i = a; i >= b; i--)
#define x               first
#define y               second
#define ii              pair <int, int>
#define iii             pair <ii, int>
#define iv              pair <ii, ii>
#define maxN            200005
#define ll              long long
#define inf             (int) 2e9
#define mode            1000000007

using namespace std;

int n, k;
char a[maxN];

bool ok(int u, int v) {
    FOR(i, u, v) if(a[i] == 'Y') return false;
    if(a[u - 1] == 'N') return false;
    if(a[v + 1] == 'N') return false;
    return true;
}

void solve() {
    cin >> n >> k >> a + 1;
    int ans = 0, cur = 0;
    FOR(u, 1, n) {
        if(a[u] == 'N') cur++, ans = max(ans, cur);
        else cur = 0;
    }
    if(ans > k) {cout << "NO"; return;}
    FOR(u, 1, n - k + 1) {
        int v = u + k - 1;
        if(ok(u, v)) {cout << "YES"; return;}
    }
    cout << "NO";
}

//#define AN "something"

int main() {
    #ifdef AN
        freopen(AN".inp", "r", stdin);
        freopen(AN".out", "w", stdout);
    #else
        //freopen("main.inp", "r", stdin);
    #endif // AN
    solve();
}

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define PI 3.1415926535
using namespace __gnu_pbds;
using namespace std;

typedef long long ll;
typedef pair <ll, ll> pll;

bool check(string &s, ll k) {
    ll cnt = 0;
    for(auto i: s) {
        if(i == 'N') cnt++;
        else cnt = 0;
        if(cnt > k) return false;
    }
    return true;
}

int main(){
    ios_base:: sync_with_stdio(0);
    //start();
    ll n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    if(!check(s, k)) {
        cout << "NO";
        return 0;
    }
    if(k == 0) {
        cout << "YES";
        return 0;
    }
    for(ll i = 0; i < n; i++) {
        if((s[i] == '?' || s[i] == 'N') && (i == 0 || s[i - 1] != 'N')) {
            ll cnt = 0;
            while(i + cnt < n && ((s[i + cnt] == '?' && cnt < k) || s[i + cnt] == 'N')) {
                cnt++;
            }
            //cout << cnt << endl;
            if(cnt == k) {
                cout << "YES";
                return 0;
            }
        }
    }
    cout << "NO";
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

int32_t main() {
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;

    for (int i = 0; i < n; i++) {
        int j = i;
        while (j < n && s[j] == 'N') {
            j++;
        }

        if (j - i > k) {
            cout << "NO\n";
            return 0;
        }
    }

    vector<int> p;
    for (int i = 0; i < n; i++) {
        if (s[i] == 'Y') {
            p.push_back(i);
        }
    }

    bool found = false;
    for (int i = 0; i <= n - k; i++) {
        bool has_yes = false;
        int idx = lower_bound(p.begin(), p.end(), i) - p.begin();
        has_yes = (idx < (int)p.size()) && p[idx] < i + k;
        if (has_yes) continue;

        if ((i - 1 < 0 || s[i - 1] == 'Y' || s[i - 1] == '?') && (i + k >= n || s[i + k] == 'Y' || s[i + k] == '?')) {
            found = true;
            break;
        }
    }

    cout << (found ? "YES" : "NO") << '\n';

    return 0;
}

#include "bits/stdc++.h"
using namespace std;
#include "vector"
#define endl '\n'
#ifndef dgb
#define dbg(...)
#define dbgv(x)
#define debug(...)
#endif
#define pb push_back
#define eb emplace_back
#define rep(i, a, b) for(auto i = a;i != b;i++)
#define brep(i, a, b) for(auto i = a;i >= b;i--)
#define repi(i, a, b) for(auto i = a;i <= b;i++)
template<class t>t mag(t a){return a>0?a:-a;}
template <class T, class U>auto cdiv(T num,U den){return (num/den)+((num%den)>0);}
std::ifstream term("/dev/tty");std::string tempstring;
using ll=long long;using ii=pair<int,int>;using vi=vector<int>;
using vl=vector<ll>;using vii = vector<ii>;
const int &sij = 110;const ll &mod = 1000000007ll;
int n, k, dp[sij][4];
string s;
int dfs(int ind, int state){
  debug(ind, state);
  if(ind == n and state == 2){
    cout << "YES";
    exit(0);
  }
  if(ind == n)  return 0;
  if(dp[ind][state] != -1)  return dp[ind][state];
  dp[ind][state] = 0;
  int mini = ind + 1, maxi = min(n, ind + k + 1);
  repi(x, mini, maxi){
    if(s[x] == 'Y'){
      if(ind + k + 1 == x){
        dp[ind][state] |= dfs(ind + k + 1, 2);
      }
      return dp[ind][state] |= dfs(x, state);
    }
    if(s[x] == '?'){
      if(ind + k + 1 == x){
        dp[ind][state] |= dfs(ind + k + 1, 2);
      }
      dp[ind][state] |= dfs(x, state);
    }
  }
  return dp[ind][state];
};
int esc(int tc){
  cin >> n >> k >> s;
  s.push_back('Y');
  int cmini = 0, cons = 0;
  repi(i, 0, n){
    if(s[i] == 'N') cons++;
    else{
      cmini = max(cmini, cons);
      cons = 0;
    }
  }
  if(k == cmini){
    cout << "YES";return 0;
  }
  if(k < cmini){
    cout << "NO";return 0;
  }
  debug(n, k);
  memset(dp, -1, sizeof(dp));
  repi(i, 0, k){
    if(s[i] == 'Y'){
      if(i == k)
        dfs(i, 2);
      else
        dfs(i, 1);
      break;
    }
    else if(s[i] == '?'){
      if(i == k)
        dfs(i, 2);
      else
        dfs(i, 1);
    }
  }
  cout << "NO";
  return 0;
}
int main(){
  ios_base::sync_with_stdio(0);
#ifndef sep
  cin.tie(0);
  cout.tie(0);
#endif
  int tc = 1;
  // cin >> tc;
  for(int i = 1;i <= tc;i++)
    esc(i);
#ifdef sep
  cerr << "\n\nTime : "<<1.0* clock()/CLOCKS_PER_SEC << "s.\n\n";
#endif
}

#include <bits/stdc++.h>

using namespace std;

string s;

int main() {
 int n, k;
 cin >> n >> k >> s;
 s = "Y" + s + "Y";
queue<int> q; int d = 0; int mn = 0; int ok = 0;
 for(int i = 0; i <= n+1; i++) {
  while(q.size() && i - q.front() - 1 > k) q.pop();
  if(s[i] != 'N') {
   if(q.size() && i - q.front() - 1 == k) ok = 1;
   d = 0;
   if(s[i] == 'Y') while(q.size()) q.pop();
   q.push(i);
  }
  else mn = max(mn, ++d);
 }
 if(ok && mn <= k) cout << "YES" << endl;
 else cout << "NO" << endl;
}

#include <bits/stdc++.h>
using namespace std;

template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl

using ll = long long;

const ll mod = 1e9+7;
const int maxn = 1e6 + 5;

int n, k;
string S;

bool test(int start) {
    string s = S;
    int cur = 0;
    for (int i=0; i<start; i++) {
	if (s[i] == '?' || s[i] == 'Y') {
	    s[i] = 'Y';
	    cur = 0;
	} else if (s[i] == 'N') {
	    cur++;
	}
	if (cur>k) return false;
    }

    if (start>0 && s[start-1] == 'N') {
	return false;
    }

    for (int i=start; i<start+k; i++) {
	if (s[i] == 'Y') {
	    return false;
	}
    }

    if (start+k<n && s[start+k] == 'N') {
	return false;
    }

    cur = 0;
    for (int i=start+k; i<n; i++) {
	if (s[i] == '?' || s[i] == 'Y') {
	    s[i] = 'Y';
	    cur = 0;
	} else if (s[i] == 'N') {
	    cur++;
	}
	if (cur>k) return false;
    }

    return true;
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);  cout.tie(0);

    cin>>n>>k;
    cin>>S;

    for (int i=0; i+k-1<n; i++) {
	if (test(i)) {
	    out("YES");
	}
    }

    cout<<"NO\n";
    return 0;
}

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

	typedef tree<
			int,
			null_type,
			less<int>,
			rb_tree_tag,
			tree_order_statistics_node_update>
	ordered_set;

#define ll long long
ll check(string str){
	ll ans=0,temp=0;
	for(int i=0;i<(int)str.length();i++){
		if(str[i]=='N') temp++;
		else{
			ans=max(ans,temp);
			temp=0;
		}
	}
	return max(ans,temp);
}

int main(){
	ios::sync_with_stdio(false);cin.tie(0);
	ll n,k;cin>>n>>k;
	string str;cin>>str;
	for(int i=0;(i+k-1)<(int)str.length();i++){
		ll j=i+k-1;
		string temp=str;
		for(int x=0;x<i;x++){
			if(temp[x]=='?'){
				temp[x]='Y';
			}
		}
		for(int x=i;x<=j;x++){
			if(temp[x]=='?'){
				temp[x]='N';
			}
		}
		for(int x=j+1;x<(int)str.length();x++){
			if(temp[x]=='?'){
				temp[x]='Y';
			}
		}
		if(check(temp)==k) {
			cout<<"YES"<<endl;
			return 0;
		}
	}
	cout<<"NO"<<endl;
	return 0;

}

#include<bits/stdc++.h>
using namespace std;

#define ll       long long int
#define ull      unsigned long long int
#define pb       push_back
#define vpop     pop_back
#define mp       make_pair
#define ff       first
#define ss       second
#define clz(x)   __builtin_clz(x)       //count leading zeroes
#define ctz(x)   __builtin_ctz(x)       //count trailing zeroes
#define sbts(x)  __builtin_popcount(x) //count set bits
#define ps(x, y) fixed << setprecision(y) << x
#define all(v)   v.begin(), v.end()
#define umap	 unordered_map
const int MOD  =  1e9 + 7;
const ll INF   =  1e12;
int n, k;
int memo[101][101][101];

int solve(string &str, int i, int N, int _max) {
    _max = max(N, _max);
    int &a = memo[i][N][_max];
    if(a != -1) return a;
    if(i == n) {
        if(_max == k)  return a = 1;
        return a = 0;
    }
    if(str[i] == 'Y')
        return a = solve(str, i+1, 0, _max);
    else if(str[i] == 'N')
        return a = solve(str, i+1, N+1, _max);
    else {
        if(solve(str, i+1, 0, _max))   return a = 1;
        return a = solve(str, i+1, N+1, _max);
    }
    return a = 0;
}

int main() {
    // freopen("input.txt","r",stdin);
    // freopen("output.txt","w",stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    memset(memo, -1, sizeof(memo));
    cin >> n >> k;
    string str;
    cin >> str;
    if(solve(str, 0, 0, 0))
        cout << "YES";
    else
        cout << "NO";
    return 0;
}

#include<bits/stdc++.h>
using namespace std;

#define ll       long long int
#define ull      unsigned long long int
#define pb       push_back
#define vpop     pop_back
#define mp       make_pair
#define ff       first
#define ss       second
#define clz(x)   __builtin_clz(x)       //count leading zeroes
#define ctz(x)   __builtin_ctz(x)       //count trailing zeroes
#define sbts(x)  __builtin_popcount(x) //count set bits
#define ps(x, y) fixed << setprecision(y) << x
#define all(v)   v.begin(), v.end()
#define umap	 unordered_map
const int MOD  =  1e9 + 7;
const ll INF   =  1e12;
int n, k;
int memo[101][101][101];

// Memoization based Soution
int solve(string &str, int i, int N, int _max) {
    _max = max(N, _max);
    int &a = memo[i][N][_max];
    if(a != -1) return a;
    if(i == n)  return a = (_max == k);
    if(str[i] != 'N') {
        bool temp1 = solve(str, i+1, 0, _max);
        if(str[i] == 'Y' || temp1)   return a = temp1;
    }
    return a = solve(str, i+1, N+1, _max);
}

int main() {
    ios_base::sync_with_stdio(false);   cin.tie(NULL);
    memset(memo, -1, sizeof(memo));
    cin >> n >> k;
    string str; cin >> str;
    cout << (solve(str, 0, 0, 0)? "YES": "NO");
    return 0;
}

#include<bits/stdc++.h>
using namespace std;

#define ll       long long int
#define ull      unsigned long long int
#define pb       push_back
#define vpop     pop_back
#define mp       make_pair
#define ff       first
#define ss       second
#define clz(x)   __builtin_clz(x)       //count leading zeroes
#define ctz(x)   __builtin_ctz(x)       //count trailing zeroes
#define sbts(x)  __builtin_popcount(x) //count set bits
#define ps(x, y) fixed << setprecision(y) << x
#define all(v)   v.begin(), v.end()
#define umap	 unordered_map
const int MOD  =  1e9 + 7;
const ll INF   =  1e12;
int n, k;
int memo[101][101][101];

int solve(string &str, int i, int N, int _max) {
    _max = max(N, _max);
    int &a = memo[i][N][_max];
    if(a != -1) return a;
    if(i == n)  return a = ((_max == k)? 1: 0);
    if(str[i] != 'N') {
        bool temp1 = solve(str, i+1, 0, _max);
        if(str[i] == 'Y' || temp1)   return a = temp1;
    }
    return a = solve(str, i+1, N+1, _max);
}

int main() {
    ios_base::sync_with_stdio(false);   cin.tie(NULL);
    memset(memo, -1, sizeof(memo));
    cin >> n >> k;
    string str; cin >> str;
    cout << (solve(str, 0, 0, 0)? "YES": "NO");
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

// IIT se hain BC!  //

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int n,k;
	cin>>n>>k;
	char str[n];
	cin>>str;
	bool flag=false;
	for (int i = 0; i <= n-k; ++i){
		int count=0,qm=0,fqm=-1;
		bool flag1=false;
		bool flag2=false;
		for (int j = 0; j < k; ++j){
			if(str[i+j]!='Y')
				count+=1;
			if(str[i+j]=='?'){
				if(qm==0)
					fqm=i+j;
				qm+=1;
			}
		}
		if(count==k){
			// cout<<str[i+k]<<" HERE"<<endl;
			if(i>0&&str[i-1]=='N'){
				if(qm==0){
				// cout<<"here1"<<endl;
				flag=false;
				break;
				}
				else{
					str[fqm]='Y';
					continue;
				}

			}
			if(i<n-k&&str[i+k]=='N'){
				if(qm==0){
				// cout<<i+k<<" here2"<<endl;
				flag=false;
				break;
				}
				else{
					str[fqm]='Y';
					continue;
				}
			}
			flag=true;
		}
	}
	if(flag)
		cout<<"YES"<<endl;
	else
		cout<<"NO"<<endl;

	return 0;
}

#include <algorithm>
#include <vector>
#include <iostream>
#include <map>
#include <fstream>
#include <set>
#include <queue>
#include <cmath>
#define all(x) x.begin(), x.end()

using namespace std;
typedef long long ll;

int main() {
	cin.tie(0), cout.tie(0), ios_base::sync_with_stdio(0);
	string s;
	int n, k;
	cin >> n >> k >> s;
	s = s + '8';
	vector<int>pr(s.size() + 1, 0), pp(s.size() + 1, 0);
	for (int i = s.size() - 2; i >= 0; --i) {
		if (s[i] == 'N')pp[i] = pp[i + 1] + 1;
		if (s[i] != 'Y')pr[i] = pr[i + 1] + 1;
		//cout << i << ": \n";
		//cout << "chain: " << pr[i] << "\n";
		//cout << "have n: " << pp[i] << "\n";
	}
	bool ok = 0;
	for (int i = 0; i < s.size(); ++i) {
		if (pr[i] >= k && s[i + k] != 'N') {
			if (i > 0 && s[i - 1] != 'N' || i == 0) {
				ok = 1;
				//cout << i << " " << pr[i]<<"\n";
			}
		}
	}
	for (int i = 0; i < s.size() - 1; i++) {
		if (pp[i] > k) {
			cout << "NO"; exit(0);
		}
	}
	if (ok)cout << "YES";
	else cout << "NO";
	return 0;
}/*
 12 2 N?N

 12 2 YYYYYN?N

 0 6
 N??NN?NNY

 0 7
 N??NN??NY

 */

//I read the news today, oh boy
//About a lucky man who made the grade

#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define sz(x) int((x).size())
#define all(v) (v).begin(),(v).end()
#define trace(x) cerr << #x << " = " << x << endl
#define fastio ios_base::sync_with_stdio(0);cin.tie(0)
#define For(i,a,b) for(int i = int(a); i < int(b); ++i)
#define roF(i,a,b) for(int i = int(a); i >= int(b); i--)
using namespace std;

typedef long long ll;
typedef pair<int,int> ii;

int dp[1000];
int here[1000][1000];

int solve(string s){
	memset(dp,0,sizeof(dp));
	dp[0]=(s[0]=='N');
	For(i,1,sz(s)){
		if(s[i]!='N')dp[i]=0;
		else dp[i]=dp[i-1]+1;
	}
	int mx=0;
	For(i,0,sz(s))mx=max(mx,dp[i]);
	return mx;
}

int main(){
	fastio;
	int n,k;cin>>n>>k;
	string s;cin>>s;
	int mn=solve(s);
	if(k<mn){
		cout<<"NO"<<endl;
		return 0;
	}
	if(k==0){
		cout<<"YES"<<endl;
		return 0;
	}
	bool find=false;
	s.pb('Y');
	For(i,0,n)For(tam,1,i+2){
		if(s[i+1]=='N')continue;
		here[i][tam]=true;
		For(j,i-tam+1,i+1)if(s[j]=='Y')
			here[i][tam]=false;
		//if(i==11&&tam==7)trace(here[i][tam]);
		if(i-tam>=0&&s[i-tam]=='N')here[i][tam]=false;
		if(tam==k&&here[i][tam])find=true;
	}
	if(find)cout<<"YES"<<endl;
	else cout<<"NO"<<endl;

	return 0;
}

//#include <bits/stdc++.h>
#include <iostream>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <vector>
#include <deque>
#include <stack>
#include <fstream>
#include <cmath>
#include <cassert>
using namespace std;

#define MOD 1000000007

vector<uint64_t> factors(uint64_t x) {
    set<uint64_t> fac;
    vector<uint64_t> space;
    for (uint64_t i = 1; i <= uint64_t(sqrt(x)); i++) {
        if (x % i == 0) {
            fac.insert(x / i);
            fac.insert(i);
        }
    }

    for (auto& y : fac) {
        space.push_back(y);
    }
    return space;
}

int main() {
	std::ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);

	uint64_t n, k;
	cin >> n>> k;
    string s;
    cin >> s;
    int maxi = 0;
    int curr = 0;
    for (int i = 0; i < s.size(); i++) {
        if (s[i] == 'N') {
            curr++;
        }
        else {
            maxi = max(maxi, curr);
            curr = 0;
        }
    }
    maxi = max(maxi, curr);
    if (maxi > k) {
        cout << "NO" << endl;
        return 0;
    }
    else {
        if (maxi == k) {
            cout << "YES" << endl;
            return 0;
        }
        else {
            for (int i = 0; i <= s.size()-k; i++) {
                bool valid = true;
                if (i > 0 && s[i - 1] == 'N') continue;
                for (int j = 0; j < k; j++) {
                    if (s[i + j] == 'Y') {
                        valid = false;
                        break;
                    }
                }
                if (valid) {
                    if (i+k==s.size() || (i + k < s.size() && s[i + k] != 'N')) {
                        cout << "YES" << endl;
                        return 0;
                    }
                }
            }
            cout << "NO" << endl;
            return 0;
        }
    }

	return 0;
}

//Author - Rahil Malhotra
#include <bits/stdc++.h>
using namespace std;

#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define int long long
#define endl "\n"

int n,k;
string s;
int cache[101][105];
int dp(int pos,int tk)
{
    if(tk>k)
        return -1e18;
    if(pos==n)
        return tk==k;
    int ans=tk==k;
    if(cache[pos][tk]!=-1)
        return cache[pos][tk];
    if(s[pos]!='?')
        return cache[pos][tk]=ans+dp(pos+1,(s[pos]=='N')?tk+1:0);
    return cache[pos][tk]=ans+max(dp(pos+1,tk+1),dp(pos+1,0));
}
int32_t main()
{
    IOS;
    cin>>n>>k>>s;
    memset(cache,-1,sizeof(cache));
    cout<<((dp(0,0)>0)?"YES":"NO");
}

//Author - Rahil Malhotra
#include <bits/stdc++.h>
using namespace std;

#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define int long long
#define endl "\n"

int n,k;
string s;
int cache[101][105][105];
int dp(int pos,int tk,int maxi)
{
    if(pos==n)
        return maxi==k;

    if(maxi>k)maxi=k+1;
    if(tk>k)tk=k+1;
    if(cache[pos][tk][maxi]!=-1)
        return cache[pos][tk][maxi];
    if(s[pos]!='?')
        return cache[pos][tk][maxi]=dp(pos+1,(s[pos]=='N')?tk+1:0,max(maxi,s[pos]=='N'?tk+1:0));
    return cache[pos][tk][maxi]=max(dp(pos+1,tk+1,max(maxi,tk+1)),dp(pos+1,0,maxi));
}
int32_t main()
{
    IOS;
    cin>>n>>k>>s;
    memset(cache,-1,sizeof(cache));
    cout<<((dp(0,0,0)>0)?"YES":"NO");
}

#include <bits/stdc++.h>
using namespace std;

const int N = 105;

char s[N];

bool dp[N][N][2];

bool solveDp(int ind,int cons,int g,int n,int k) {
    if(cons>k) {
        return false;
    }
    if(ind==n) {
        if(g) {
            return true;
        }
        else {
            return false;
        }
    }
    if(dp[ind][cons][g]) {
        return false;
    }
    dp[ind][cons][g] = true;
    if(s[ind]=='?') {
        int tmp = 0;
        int ng = g;
        if(tmp==k) {
            ng = 1;
        }
        if(solveDp(ind+1,tmp,ng,n,k) ){
            return true;
        }
        tmp = cons+1;
        ng = g;
        if(tmp==k) {
            ng = 1;
        }
        if(solveDp(ind+1,tmp,ng,n,k) ){
            return true;
        }
    }
    else if(s[ind]=='Y') {
        int tmp = 0;
        int ng = g;
        if(solveDp(ind+1,tmp,ng,n,k) ) {
            return true;
        }
    } else {
        int tmp = cons+1;
        int ng = g;
        if(tmp==k) {
            ng = 1;
        }
        if(solveDp(ind+1,tmp,ng,n,k) ) {
            return true;
        }
    }
    return false;
}

void solve() {
    int n,k;
    scanf("%d %d",&n,&k);
    scanf("%s",s);
    int g = 0;
    if(k==0) {
        g = 1;
    }
    if(solveDp(0,0,g,n,k)) {
        cout<<"YES\n";
    } else {
        cout<<"NO\n";
    }
}

int main()
{
    solve();
}

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
char a[250];
int main()
{
    int n,k;
    scanf("%d%d",&n,&k);
    getchar();
    for(int i=1; i<=n; i++)
    {
        scanf("%c",&a[i]);
    }
    // printf("%s",a);
    int p=1,kk,maxx=0,flag=0,kkk,sum=0;
    for(int i=1; i<=n; i+=p)
    {
        //printf("i=%d\n",i);
        if(a[i]=='N')
        {
            kk=0;
            for(int j=i; j<=n; j++)
            {
                if(a[j]=='N')
                {
                    kk++;
                }
                else
                {
                    p=kk;
                    break;
                }
            }
            maxx=max(maxx,kk);
            kkk=kk;
            //  printf("%d\n",kk);
            if(kk<k)
            {
                for(int j=i-1; j>=1; j--)
                {
                    if((a[j]=='?'&&j==1)||(a[j]=='?'&&a[j-1]!='N'))
                    {
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                        kk++;
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                    }
                    else if(a[j]=='?'&&a[j-1]=='N')
                    {
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                        kk++;
                    }
                    else if(a[j]=='N')
                        kk++;
                    else if(a[j]=='Y')
                    {
                        break;
                    }
                }
                if(flag==0)
                {
                    for(int j=i+p; j<=n; j++)
                    {
                        if((a[j]=='?'&&j==n)||(a[j]=='?'&&a[j+1]!='N'))
                        {
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kkk++;
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                        }
                        else if(a[j]=='?'&&a[j+1]=='N')
                        {
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kkk++;
                        }
                        else if(a[j]=='N')
                            kkk++;
                        else if(a[j]=='Y')
                        {
                            break;
                        }
                    }
                }

            }
            //   printf("%d %d %d\n",i,kk,kkk);

            //  maxx=max(maxx,kkk);
        }
        else
        {
            p=1;
        }
    }
    if(flag==0)
    {
        int pos=1;
        for(int i=n; i>=1; i--)
        {
            if(a[i]=='N')
            {
                pos=i+2;
                break;
            }
        }
        kk=0;
       // printf("%d\n",pos);
        for(int i=pos; i<=n; i++)
        {
            if(a[i]=='?')
            {
                if(kk==k)
                {
                    flag=1;
                    break;
                }
                kk++;
                if(kk==k)
                {
                    flag=1;
                    break;
                }
            }
            else
            {
                kk=0;
            }
        }
    }

    // printf("%d\n",flag);
    if(maxx==k||(maxx<k&&flag))
        printf("YES\n");
    else printf("NO\n");
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <ctime>
#include <cmath>
#include <string>
#include <stdlib.h>
#include <fstream>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <deque>
#include <iterator>
#include <iomanip>
#include <climits>
#include <numeric>
#include <cstring>
#include <list>
using namespace std;
#define ll long long int

const int MAXN = 2e5 + 1;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n, k;
    string s;
    cin >> n >> k >> s;

    int cnt = 0, a = 0;

    for(int i = 0; i < n; ++i){
        if(s[i] == 'N'){
            if(i && s[i - 1] == 'N') cnt++;
            else cnt = 1;
        }
        if(s[i] != 'N') cnt = 0;

        a = max(a, cnt);
    }

    if(a > k){
        cout << "NO\n";
        return 0;
    }

    if(a == k){
        cout << "YES\n";
        return 0;
    }

    for(int i = 0; i <= n - k; ++i){
        bool ok = true;

        if(i && s[i - 1] == 'N') continue;
        if(i + k != n && s[i + k] == 'N') continue;

        for(int j = i; j < i + k; ++j){
            if(s[j] == 'Y'){
                ok = false;
                break;
            }
        }

        if(ok){
            cout << "YES\n";
            return 0;
        }
    }

    cout << "NO\n";
}

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <cstring>
#include <string>
#include <vector>
#define MIN 1<<31-1
#define REP(i,n) for(int i = 0; i < (n); i++)
typedef long long int ll;
char NN[10000];
int zu[10000];
using namespace std;
int main()
{
	int n,k,l,r;
	cin>>n>>k;
	l=0;r=0;
	int flag=0;
	int nowl=0;
	int cou=0;
	for(int i=0;i<n;i++)
	{
		cin>>NN[i];
	}
	int i;
	for(i=0;i<n;i++)
	{
		if((NN[i]=='N'||NN[i]=='?')&&NN[i-1]!='N')
		{
			int w;
			for(w=1;w<k;w++)
				if(w+i>=n||NN[w+i]=='Y')
					break;
			if(w==k&&NN[i+w]!='N')
			{
				break;
			}
		}
	}
	int out=0;
	if(i!=n||k==0)
		out=1;
	int mi=0;
	int nmi=0;
	for(i=0;i<n;i++)
	{
		if(NN[i]=='N')
		{
			nmi++;
		}
		else
		{
			mi=max(mi,nmi);
			nmi=0;
		}
	}
	mi=max(mi,nmi);
	if(out==1&&mi<=k)
		cout<<"YES";
	else
		cout<<"NO";
	return 0;
}

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

int main(){

    //Stepan's Series

    int i, n, k, prev, now, ans;
    string s;

    cin>>n>>k;
    cin>>s;

    prev=0;
    ans=0;

    for (i=0;i<n;i++){
        if (s[i]=='N'){
            now=prev+1;
        }
        else {
            now=0;
        }
        prev=now;
        ans=max(ans, now);
    }

    if (ans==k){
        cout<<"YES\n";
    }
    else if (ans<k){
        int j;
        bool b=true;
        vector <int> v;
        for (i=0;i<n;i++){
            if (s[i]=='Y'){
                v.push_back(i);
                b=true;
            }
            else if (s[i]=='?'){
                if (i>0){
                    if (s[i-1]!='N'){
                        v.push_back(i);
                    }
                }
                else {
                    v.push_back(i);
                }
                b=true;
            }
            else {
                if (b){
                    v.push_back(i);
                    b=false;
                }
            }
        }
        for (i=0;i<v.size();i++){
            prev=0;
            ans=0;
            for (j=v[i];j<n;j++){
                if (s[j]=='N'){
                    now=prev+1;
                }
                else if (s[j]=='?'){
                    if (ans<k){
                        now=prev+1;
                    }
                    else {
                        now=0;
                    }
                }
                else {
                    now=0;
                }
                prev=now;
                ans=max(ans, now);
            }
            if (ans==k){
                break;
            }
        }
        if (ans==k){
            cout<<"YES\n";
        }
        else {
            cout<<"NO\n";
        }
    }
    else {
        cout<<"NO\n";
    }

    return 0;
}

#include <iostream>
#include <vector>
#include <string>

using namespace std;

bool check(string &s, int k, int ind)
{
    int cntr = 0;
    for (int i = ind; i < s.size(); i++)
    {
        if (s[i] == 'N' || s[i] == '?')
        {
            cntr++;
        }
        else if (s[i] == 'Y' && cntr < k)
            return false;
        if (cntr == k)
        {
            if (i == s.size() - 1)
                return true;
            else if (s[i+1] != 'N')
                return true;
            else
                return false;
        }
    }
    return false;
}

int main()
{
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;

    int cnt = (s[0] == 'N' ? 1 : 0), maxcnt = 0;

    for (int i = 1; i < s.size(); i++)
    {
        if (s[i] == 'N' && s[i-1] == 'N')
            cnt++;
        else if (s[i] == 'N')
            cnt = 1;
        else
        {
            maxcnt = max(cnt, maxcnt);
            cnt = 0;
        }
        maxcnt = max(cnt, maxcnt);
    }
    maxcnt = max(cnt, maxcnt);
    if (maxcnt > k)
    {
        cout << "NO" << endl;
        return 0;
    }
    else if (maxcnt == k)
    {
        cout << "YES" << endl;
        return 0;
    }

    bool ok = check(s, k, 0);
    if (ok)
    {
        cout << "YES" << endl;
        return 0;
    }
    for (int i = 1; i < s.size(); i++)
        if ((s[i] == 'N' || s[i] == '?') && s[i-1] != 'N')
        {
            ok = check(s, k, i);
            if (ok)
                break;
        }

    if (ok)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int dp[101][101][101], n, k;
string s;
int solve(int i, int N, int mx){
	if (i == n)
		return mx == k ? 1 : 0;
	int &ret = dp[i][N][mx];
	if (~ret)return ret;
	if (s[i] == 'N'){
		mx = max(mx, N + 1);
		return ret = solve(i + 1, N + 1, mx);
	}
	if (s[i] == 'Y'){
		mx = max(mx, N);
		return ret = solve(i + 1, 0, mx);
	}
	int c1 = solve(i + 1, 0, max(mx, N));
	int c2 = solve(i + 1, N + 1, max(mx, N + 1));
	return ret = max(c1,c2);
}
int main(){
	memset(dp, -1, sizeof dp);
	cin >> n >> k >> s;
	cout << (solve(0, 0, 0) ? "YES" : "NO");
}

#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <algorithm>
#include <fstream>
#include <iomanip>
#include <iterator>
#include <sstream>
#include <set>
#include <map>
#include <unordered_map>
#include <list>
#include <ctime>
#include <queue>
#include <cmath>
#include <stack>
#include <functional>
#include <memory>
#include <tuple>
#include <utility>

using namespace std;

#define __int64 long long
const double pi = atan2(0.0, -1.0);
const int inf = 2147483647;

//For working whith file in my PC
#ifdef RED
//#include "acm.h"
//#include "Test.h"
ifstream in;
ofstream out;
#define cin in
#define cout out
#endif
// cout << fixed << setprecision(a) <<

class Global // For zeroing fields in unit test
{
public:

	int n, i, k;
	string s;
	bool yes = false;
	char ch;
	void solve()
	{
		cin >> n >> k >> s;
		vector<vector<int>> v(n+2);
		s += 'Y';
		v[0] = { 0};

		for (i = 1; i<=n+1;i++)
		{
			ch = s[i-1];
			if (ch == 'Y')
			{
				if (v[i - 1][0] > k)
				{
					cout << "NO";
					return;
				}
				for (const auto& it : v[i - 1])
				{
					if (it == k) yes = true;
				}
				v[i] = { 0 };
			}
			if (ch == 'N')
			{
				v[i] = v[i - 1];
				for (auto& it : v[i])
				{
					++it;
				}
			}
			if (ch == '?')
			{
				v[i] = { 0 };
				for (auto& it : v[i-1])
				{
					v[i].push_back(it + 1);
				}
				for (const auto& it : v[i - 1])
				{
					if (it == k) yes = true;
				}
			}
		}

		if (yes)
		{
			cout << "YES";
		}
		else
		{
			cout << "NO";
		}
	}

};

#ifndef UNIT_TESTING

int main()
{
	//srand(time(0));
	//ios_base::sync_with_stdio(0);
	//cin.tie(0);

#ifdef RED

	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	in.open("input.txt");
	out.open("output.txt");

	int amount_TEST = 1;
	cin >> amount_TEST;
	for (int amount_test = 1; amount_test <= amount_TEST; ++amount_test)
	{
#endif

		vector<Global> global;

		int t = 1;
		//	cin >> t;
			//		easy_factory();
		for (; t--;)
		{
			global.clear();
			global.resize(1);
			global[0].solve();
		}

#ifdef RED
		cout << "\nКонец " << amount_test << " Теста\n";
	}
#endif
}
#endif UNIT_TESTING

#include <bits/stdc++.h>
#define mod 1000000007
#define INF 1000000000000000007LL
#define SZ 200009
#define ull unsigned long long
#define ll long long int
#define ld long double
#define fi first
#define se second
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define all(v) ((v).begin()), ((v).end())
#define ios ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define db(...) ZZ(#__VA_ARGS__, __VA_ARGS__)
#define dbvv(v) cout << "Printing "#v << " --> \n"; for(ll i=0;i<v.size();i++) {for(ll j=0;j<v[i].size();j++) cout << v[i][j] << " "; cout << "\n";}
#define dbv(st) cout << "Printing "#st << " --> \n"; for(auto i=st.begin();i!=st.end();i++) cout << *i << " "; cout << "\n";
#define dbvp(st) cout << "Printing "#st << " --> \n"; for(auto i=st.begin();i!=st.end();i++) cout << i->first << " " << i->second << "\n"; cout << "\n";
#define dbmp(mp) cout << "Printing "#mp << " --> \n"; for(auto i=mp.begin();i!=mp.end();i++) cout << #mp"[" << i->first << "]"<< " = " << i->second << "\n";
#define dbar(ar,st,en) cout << "Printing "#ar << " --> \n"; for(auto it=st;it!=en;it++) cout << *it << " "; cout << "\n";
#define dbmar(ar,rowz,colz) cout << "Printing "#ar << " --> \n"; for(auto i=0;i<rowz;i++) {for(auto j=0;j<colz;j++) cout << ar[i][j] << " "; cout << "\n";}
template <typename Arg1>void ZZ(const char* name, Arg1&& arg1){std::cout << name << " = " << arg1 << std::endl;}
template <typename Arg1, typename... Args>void ZZ(const char* names, Arg1&& arg1, Args&&... args)
{
    const char* comma = strchr(names + 1, ',');
    std::cout.write(names, comma - names) << " = " << arg1;
    ZZ(comma, args...);
}
using namespace std;

ll to_ll(string &s)
{
	ll i,ret=0,p=1;
	for(i=(ll)s.length()-1;i>=0;i--) ret+=(s[i]-'0')*p, p*=10LL;
	return ret;
}
ll gcd(ll x,ll y)
{
	if(y==0) return x;
	return gcd(y,x%y);
}
ll pwr(ll base,ll expo,ll m)
{
	if(base==0) return 0LL;
	if(expo==0) return (1LL%m);
	if((expo&1)==0) {ll temp=pwr(base,expo>>1,m); return (temp*temp)%m;}
	return ((base%m)*pwr(base,expo-1,m))%mod;
}
ll n,k;
string s;
ll chk(string &x)
{
	//db(x);
	ll mx=0;
	ll i,j;
	for(i=0;i<n;i++)
	{
		ll cnt=0;
		for(j=i;j<n;j++)
		{
			if(x[j]!='N') break;
			cnt++;
		}
		mx=max(mx,cnt);
	}
	return mx;
}
int main()
{
	ios;
	cin>>n>>k;
	cin>>s;
	if(k==0)
	{
		if(s=="Y"||s=="?") cout << "YES\n";
		else cout << "NO\n";
		return 0;
	}
	ll i,j,it;
	for(i=0;i<n;i++)
	{
		for(j=i;j<n;j++)
		{
			if(j-i+1!=k) continue;
			ll cnt=count(s.begin()+i,s.begin()+j+1,'Y');
			if(cnt>0) continue;
			string cpy=s;
			for(it=j+1;it<n;it++) if(cpy[it]=='?') cpy[it]='Y';
			for(it=i-1;it>=0;it--) if(cpy[it]=='?') cpy[it]='Y';
			for(it=i;it<=j;it++) if(cpy[it]=='?') cpy[it]='N';
			if(chk(cpy)!=k) continue;
			cout << "YES\n";
			return 0;
		}
	}
	cout << "NO\n";
	return 0;
}

#include <iostream>
#include <string>

using namespace std;

int main()
{
	string s;
	short n, k, a = 0, max = 0, maxnow = 0, min = 0, minnow = 0, f = 1, b;
	cin >> n >> k >> s;
	for (; a < n; a++)
	{
		if (s[a] != 'Y') { maxnow++; if (max < maxnow) max++; }
		else maxnow = 0;
		if (s[a] == 'N') { minnow++; if (min < minnow) min++; }
		else minnow = 0;
	}
	if ((k < min) | (k > max)) { cout << "NO"; return 0; }
	if ((k == min) | (k == max)) { cout << "YES"; return 0; }
	for (a = 0; a < k; a++)
	{
		if (s[a] == 'Y') { f = 0; break; }
	}
	if (f & (s[a] != 'N')) { cout << "YES"; return 0; }
	n -= k;
	f = 1;
	for (a = 1; a < n; a++)
	{
		for (b = a; b < a + k; b++)
		{
			if (s[b] == 'Y') { f = 0; break; }
		}
		if (f & (s[a - 1] != 'N') & (s[b] != 'N')) { cout << "YES"; return 0; }
		else f = 1;
	}
	f = 1;
	for (a = n; a < n + k; a++)
	{
		if (s[a] == 'Y') { f = 0; break; }
	}
	if (f & (s[n - 1] != 'N')) { cout << "YES"; return 0; }
	else cout << "NO";
	return 0;
}

#include <bits/stdc++.h>
using namespace std;

int main(){
	int n , k;
	cin >> n >> k;
	char s [n];
	cin >> s;
	bool f=false;

	for(int i=0;i<sizeof(s);i++){
		char t [n];
		for(int j=0;j<sizeof(s);j++){
			if(j>=i && j<i+k && s[j]=='?')
				t[j]='N';
			else
				t[j]=s[j];
		}
		int m=0;
		int cnt=0;
		for(int j=0;j<sizeof(s);j++){
			if(t[j]=='N')
				cnt++;
			else
				cnt=0;
			m=max(m,cnt);
		}
		if(m==k)
			f=true;
	}

	cout << (f? "YES" : "NO");
 	return 0;
}

#include <bits/stdc++.h>
using namespace std;

int n, m;
string s;

int main()
{
  cin >> n >> m;
  cin >> s;
  for(int i = 0;i < n-m+1;i++){
    if(i >= 1 && s[i-1] == 'N')continue;
    if(i+m < n && s[i+m] == 'N')continue;

    int ok = 1;
    for(int j = 0;j < m;j++){
      if(s[i+j] == 'Y'){
        ok = 0;
      }
    }
    int rep = 0;
    for(int j = 0;j < i;j++){
      if(s[j] == 'N'){
        if(++rep > m){
          ok = 0;
        }
      }else{
        rep = 0;
      }
    }
    rep = 0;
    for(int j = i+m;j < n;j++){
      if(s[j] == 'N'){
        if(++rep > m){
          ok = 0;
        }
      }else{
        rep = 0;
      }
    }
    if(ok){
      cout << "YES" << endl;
      return 0;
    }
  }
  cout << "NO" << endl;
}

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
int n, k;
string s;
int dp[105][105][105];
int solve(int ind, int cnt, int mx){
	mx = max(mx, cnt);
	if (ind == n)
		return mx == k;
	int & ret = dp[ind][cnt][mx];
	if (ret != -1)
		return ret;
	if (s[ind] == 'Y')
		ret = solve(ind + 1, 0, mx);
	else if (s[ind] == 'N')
		ret = solve(ind + 1, cnt + 1, mx);
	else
		ret = solve(ind + 1, cnt + 1, mx) || solve(ind + 1, 0, mx);
	return ret;
}
int main()
{
	cin >> n >> k >> s;
	memset(dp, -1, sizeof dp);
	if (solve(0, 0, 0))
		cout << "YES" << endl;
	else
		cout << "NO" << endl;
	return 0;
}

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main() {
	int n, k;
	string s;
	cin >> n >> k >> s;

	s = string("Y") + s + string("Y");

	int i, j, ok, found, longest, run;

	longest = 0;
	found = 0;
	run = 0;

	for (i=1; i<=n; i++) {
		if (s[i] == 'N') {
			run += 1;
		} else {
			run = 0;
		}
		if (run > longest) {
			longest = run;
		}
	}

	for (i=1; i<=n-k+1; i++) {
		ok = 1;
		for (j=i; j<i+k; j++) {
			if (s[j] == 'Y') {
				ok = 0;
			}
		}
		if (s[i-1] == 'N') {
			ok = 0;
		}
		if (s[i+k] == 'N') {
			ok = 0;
		}

		if (ok) {
			found = 1;
		}
	}

	cerr << longest << '\n';

	if (found && k >= longest) {
		cout << "YES";
	} else {
		cout << "NO";
	}
}

#include<bits/stdc++.h>
#define LL int64_t
#define LD long double;
using namespace std;

bool can(string s, int n, int k, int pos) {
    for(int i=0;i<k;i++) {
        if(s[pos+i]=='?') s[pos+i]='N';
    }
    for(int i=0;i<n;i++) if(s[i]=='?') s[i]='Y';

    int maxStreak = 0;
    int curStreak = 0;
    for(char c : s) {
        if(c=='Y') curStreak = 0;
        else curStreak++;
        maxStreak=max(maxStreak,curStreak);
    }
    return maxStreak == k;
}

int main() {
    ios::sync_with_stdio(false); cin.tie(0);
    int n,k;
    string s;
    cin>>n>>k>>s;

    bool ans = false;
    for(int i=0;i<n-k+1;i++) {
        if(can(s,n,k,i)) ans = true;
    }
    if(ans) cout<<"YES\n";
    else cout<<"NO\n";
}

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cmath>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>

using namespace std;
typedef long long LL;
const LL INF=1e17L;
const int inf=0x3f3f3f3f;
const int maxn=1e2+5;
const int Mod=1e9+7;
int dp[maxn][maxn][maxn],n,k;
string s;
int main()
{
    cin>>n>>k>>s;
    dp[0][0][0]=1;
    for(int i=1;i<=n;i++)
    {
        char c=s[i-1];
        for(int j=0;j<=k;j++)
        {
            for(int d=0;d<=j;d++)
            {
                if(dp[i-1][j][d])
                {
                    if(c=='Y')
                    {
                        dp[i][j][0]=1;
                    }
                    else if(c=='N')
                    {
                        dp[i][max(j,d+1)][d+1]=1;
                    }
                    else
                    {
                        dp[i][max(j,d+1)][d+1]=1;
                        dp[i][j][0]=1;
                    }
                }
            }
        }
    }
    bool flag=false;
    for(int i=0;i<=k;i++)
        if(dp[n][k][i]) flag=true;
    if(flag) puts("YES");else puts("NO");
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef complex<double> cplx;

#define sqr(x) ((x)*(x))
#define pb push_back
#define X first
#define Y second
#define sit(a) set<a>::iterator
#define mit(a,b) map<a,b>::iterator

const ll mod=1000000007LL;
const int inf=0x3f3f3f3f;
const int maxn=500005,maxm=10005;
const double eps=1e-10;
const double pi=acos(-1.0);

char c[maxn];
int n,k;
bool v[maxn]={0};

bool check()
{
    int i,j;
    for(i=0;i<n;i++)
    {
        for(j=i;j<i+k&&j<n&&c[j]=='N';j++);
        if(j<n&&j==i+k&&c[j]=='N') return 0;
    }
    return 1;
}

void solve()
{
    int i,j;
    for(i=0;i+k<=n;i++)
    {
        for(j=i;j<i+k&&c[j]!='Y';j++) c[j]='N';
        if(j==i+k&&check()) {printf("YES\n");return;}
        for(j=i;j<i+k&&v[j];j++) c[j]='?';
    }
    printf("NO\n");
}

int main()
{
    int i,j;
    scanf("%d %d %s",&n,&k,c);
    for(i=0;i<n;i++) if(c[i]=='?') v[i]=1;
    solve();
    return 0;
}

#include <bits/stdc++.h>

using namespace std;

const int N = 200;

char s[N];
int n, k;
int main() {
  scanf("%d %d", &n, &k);
  scanf("%s", s);
  bool ok = 1, exact = 0;

  for (int i = 0; i < n; i++) {
    if (i + k + 1 > n) break;
    bool now = 0;
    for (int j = 0; j < k+1; j++) {
      if (s[i+j] != 'N')
        now = 1;
    }
    if (!now) {
      puts("NO");
      return 0;
    }
  }
  for (int i = 0; i < n; i++) {
    if (i + k > n) break;
    bool now = 1;
    if (i && s[i-1] == 'N') now = 0;
    if (i + k < n && s[i+k] == 'N') now = 0;
    for (int j = 0; j < k; j++)
      if (s[i+j] == 'Y')
        now = 0;
    if (now)
      exact = 1;
  }
  if (exact)
    puts("YES");
  else
    puts("NO");
  return 0;
}

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int MAXN = 2e5 + 5;
const long long MOD = 1e9 + 7;

pair<int,int> p;

int main()
{
	//freopen("input.in","r",stdin);
    //freopen("output.out","w",stdout);

	int n,k; cin >> n >> k;
	string s; cin >> s;
	int c1 = 0; int c2 = 0;
	for(int i = 0; i < n;)
	{
		if(s[i] == 'N')
		{
			int j = i;
			while(j < n && s[j] == 'N')
				j++;
			c1 = max(c1,j - i);
			i = j;
		}
		else
		{
			i++;
		}
	}
	for(int i = 0; i < n;)
	{
		if(s[i] == 'N' || s[i] == '?')
		{
			int j = i;
			while(j < n && (s[j] == 'N' || s[j] == '?'))
				j++;
			c2 = max(c2,j - i);
			i = j;
		}
		else
		{
			i++;
		}
	}
	if(c1 > k || c2 < k){
		cout << "NO";
		return 0;
	}
	if(k == 0){
		if(c1 == 0)
		{
			cout << "YES";
			return 0;
		}
	}
	for(int i = 0; i < n; ++i)
	{
		for(int j = i; j < n; ++j)
		{
			if(j - i + 1 !=  k) continue;
			else
			{
				int c = 0;
				for(int l = i; l <= j; ++l)
				{
					if(s[l] == '?' || s[l] == 'N')
						c++;
				}
				if(c == k){
					int fl = 1;
					if(i - 1 >= 0 && s[i - 1] == 'N') fl = 0;
					if(j + 1 < n && s[j + 1] == 'N') fl = 0;
					if(fl)
					{
						cout << "YES\n";
						return 0;
					}
				}
			}
		}
	}
	cout << "NO";

	return 0;

}

#include <iostream>
#include <stdio.h>
#include <cmath>
#include <math.h>
#include <string>
#include <algorithm>
#include <functional>
#include <stack>
#include <list>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <unordered_set>
#include <unordered_map>
#include <bitset>
#include <sstream>
#include <cassert>

#define PI 3.1415926535
#define ll long long
#define ull unsigned long long
#define umap unordered_map
#define uset unordered_set
#define all(a) a.begin(), a.end()
#pragma comment(linker, "/STACK:64777216")

using namespace std;

const int MAXINT = (int)2e9 + 100;
const ll MAXN = 100000;
const ll MAXVAL = 10000000;
const ll INF = (ll)1e18 + 50;
const ll MOD = (ll)1e9 + 7;
const ull HASH_MOD = 2305843009213693951;
string failMessage;

void fail()
{
	cout << failMessage;
	exit(0);
};

int f(string s)
{
	s += "Y";

	int max_len = -1, cur = 0;

	for (int i = 0; i < s.length(); i++)
	{
		if (s[i] != 'N')
		{
			max_len = max(max_len, cur);
			cur = 0;
		}
		else if (s[i] == 'N')
		{
			cur++;
		}
	}

	return max_len;
}

void solve()
{
	int n, k;
	cin >> n >> k;
	string s;
	cin >> s;

	int l = f(s);

	if (l > k)
	{
		cout << "NO";
		return;
	}

	for (int i = 0; i < n; i++)
	{
		bool good = true;
		if (i + k - 1 >= n)
			break;
		if (i > 0 && s[i - 1] == 'N')
			good = false;
		if (i + k < n && s[i + k] == 'N')
			good = false;
		for (int j = i; j < i + k; j++)
		{
			if (s[j] == 'Y')
				good = false;
		}

		if (good)
		{
			cout << "YES";
			return;
		}
	}

	cout << "NO";
}

int main()
{
	const string FILENAME = "111";
#ifndef LOCAL
	//freopen((FILENAME + ".in").data(), "r", stdin);
	//freopen((FILENAME + ".out").data(), "w", stdout);
#endif // !LOCAL

	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.precision(15);
	solve();

}

#include <bits/stdc++.h>
#define maxn 200
using namespace std;

int n, m;
char a[maxn];

int main()
{
	scanf("%d%d", &n, &m);
	scanf("%s", a + 1);

	if(m == 0)  //特判
	{
		for(int i = 1; i <= n; ++i)
		{
			if(a[i] == 'N')
			{
				printf("NO\n");
				return 0;
			}
		}
		printf("YES\n");
		return 0;
	}
	if(m == n)
	{
		for(int i = 1; i <= n; ++i)
		{
			if(a[i] == 'Y')
			{
				printf("NO");
				return 0;
			}
		}
		printf("YES");
		return 0;
	}

	int cnt = 0, ansn = 0;
	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'N')
		{
			cnt++;
		}
		else
		{
			cnt = 0;
		}

		ansn = max(ansn, cnt);
	}

	if(ansn > m)
	{
		printf("NO");
		return 0;
	}
	if(ansn == m)
	{
		printf("YES");
		return 0;
	}

	//针对？的情况
	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'Y')
			continue;
		if(i + m > n + 1)
			break;

		bool ok = true; //一开始认为是好的
		for(int k = i; k <= i + m - 1; ++k)
		{
			if(a[k] == 'Y') //判断是否是好的
			{
				ok = false;
				break;
			}
		}
		if(ok && a[i + m] != 'N' && a[i - 1] != 'N')
		{
			printf("YES");
			return 0;
		}
	 }
	 printf("NO");

	return 0;
}

#include <iostream>
#include <vector>

using namespace std;

int main() {
    int n, k;
    cin >> n >> k;
    char c;
    int cnt1 = 0, cnt2 = 0;
    int cur1 = 0, cur2 = 0;
    vector<char> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    for (int i = 0; i < n; i++) {
        c = a[i];
        if (c == '?') {
            cur1++;
            cur2 = 0;
        }
        else if (c == 'N') {
            cur2++;
            cur1++;
        }
        else if (c == 'Y') {
            cur2 = 0;
            cur1 = 0;
        }
        if (cur1 >= k) {
            if ((i == n - 1 || a[i + 1] != 'N') && (i - k == -1 || a[i - k] != 'N')) {
                cnt1 = cur1;
            }
        } else {
            cnt1 = max(cnt1, cur1);
        }
        //cout << cnt1 << '\n';
        cnt2 = max(cnt2, cur2);
    }
    //cout << cnt1 << ' ' << cnt2 << '\n';
    if (cnt1 >= k && cnt2 <= k) {
        cout << "YES\n";
    } else {
        cout << "NO\n";
    }
}

#include<bits/stdc++.h>
#define FileName      "test"
#define ll            long long
#define ld            long double
#define ull           unsigned long long
#define Debug(x)      cerr << #x << "is " << x << '\n';
#define pb            emplace_back
#define mp            make_pair
#define x             first
#define y             second
//#define LuckyAurora
//#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
//#pragma GCC optimization ("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")

using namespace std;

template<typename T> inline void Cin(T &x)
{
    char c;
    T sign = 1;
    x = 0;
    for (c = getchar(); c < '0' || c > '9'; c = getchar())
        if (c == '-') sign = -1;
    for (; c >= '0' && c <= '9'; c = getchar())
        x = x * 10 + c - '0';
    x *= sign;
}
template <typename T> inline void Out(T x) {if(x > 9) Out(x / 10); putchar(x % 10 + '0');}
template <typename T> inline void Cout(T x, char c) {if(x < 0) putchar('-'); x = abs(x); Out(x); putchar(c);}
template <typename T, typename... Args> inline void Cin(T& a, Args&... args) {Cin(a);Cin(args...);}
template <typename T, typename... Args> inline void Cout(T a, char c, Args... args) {Cout(a, c);Cout(args...);}

typedef pair<ll, ll> Point;
const int N = int(2e5) + 3;

int n, k, cnt;
bool can;
string s;

bool Check(int l, int r)
{
    if(r > n) return 0;
    for(int i = l; i <= r; ++i)
       if(s[i] == 'Y') return 0;
    if(s[l - 1] == 'N' || s[r + 1] == 'N') return 0;
    return 1;
}

void Enter()
{
     cin >> n >> k >> s;
     s = ' ' + s + ' ';
     for(int i = 1; i <= n; ++i) {
        if(Check(i, i + k - 1)) can = 1;
        if(s[i] == 'N') ++cnt;
        else cnt = 0;
        if(cnt > k) {cout << "NO"; exit(0);}
     }
     if(can) cout << "YES\n";
     else cout << "NO\n";
}

void Solve()
{

}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if(fopen(FileName".inp", "r")) {
        freopen(FileName".inp", "r", stdin);
        freopen(FileName".out", "w", stdout);
    }

    /*int nTest; cin >> nTest;
    while(nTest --)*/ Enter(), Solve();

    return 0;
}

//
//  main.cpp
//  test
//
//  Created by Максим Бачурин on 04.02.17.
//  Copyright © 2017 Максим Бачурин. All rights reserved.
//

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <utility>
#include <set>
#include <map>
#include <list>
#include <queue>
#include <algorithm>
#include <iomanip>
using namespace std;
#define all(x) (x).begin(),(x).end()
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> PII;
const ll mod = 1e9 + 7;
//const double eps = 1e-9;
const int inf = 1e9;
//const double PI = 3.1415926535897932384626433832795;
const int N = 40005;

int main()
{
    //freopen("output.txt", "r", stdin);
    //freopen("output2.txt", "w", stdout);
    ios_base::sync_with_stdio(0);
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    int t, mx;
    for(int i = 0; i <= s.size() - k; i++)
    {
        mx = 0;
        t = 0;
        for(int j = 0; j < s.size(); j++)
        {
            if(s[j] == 'N' || (s[j] == '?' && i <= j && j < i + k))
            {
                t++;
                mx = max(mx, t);
            }
            else
                t = 0;
        }
        if(mx == k)
            return cout << "YES" << endl, 0;
    }
    cout << "NO" << endl;
    return 0;
}

#include <stdio.h>
#include <bits/stdc++.h>

#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)

#define file ""

using namespace std;
using ll = long long;
using ull = unsigned long long;
using str = string;
using srt = short;

const int INF = (int)1e9 + 7;
const int mod = 998244353;
const ll inf = (ll)1e18;
const ull oo = 1000000000000001;
const int N = 200005;

signed main()
{
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	ios::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr); //freopen(file".in", "r", stdin); freopen(file".out", "w", stdout);

	int n, k;
	cin >> n >> k;
	str s;
	cin >> s;
	s = '#' + s + '#';
	int cnt = 0;
	int mx = 0;
	for (int i = 1; i <= n; ++i)
	{
		if (s[i] == 'N')
			++cnt;
		else
			cnt = 0;
		mx = max(mx, cnt);
	}
	if (k < mx || n < k)
	{
		cout << "NO";
	}
	else
	{
		for (int i = 1; i + k - 1 <= n; ++i)
		{
			bool ok = (s[i - 1] != 'N' && s[i + k] != 'N');
			for (int j = i; ok && j <= i + k - 1; ++j)
			{
				ok &= (s[j] != 'Y');
			}
			if (ok)
			{
				cout << "YES";
				return 0;
			}
		}
		cout << "NO";
	}
}

#include <bits/stdc++.h>
using namespace std;
#define x first
#define y second
#define ll long long
#define pb push_back
//////////////////////////
const int oo = 1e9 + 9;
const ll inf = 1e18 + 18;
const int max6 = 1e6 + 6;
const int modx = 1e9 + 123;
const int mody = 997;
const int base = 137;
typedef pair <int,int> ii;
//////////////////////////

int t[max6];
int n,k;

bool ok(int l,int r)
{
    int cnt = 0;
    for (int i = l; i <= r; ++i)
        cnt += t[i] == 1;

    if (cnt)
        return false;

    int cur = 0;
    for (int i = r+1; i <= n; ++i)
    {
        if (t[i] == 2)
            cur++;
        else cur = 0;
        if (cur > k)
            return false;
    }

    for (int i = 1; i < l; ++i)
    {
        if (t[i] == 2)
            cur++;
        else cur = 0;

        if (cur > k)
            return false;
    }

    return true;
}
//////////////////////////
main()
{
#define file ""
#ifndef ONLINE_JUDGE
    freopen(file"inp","r",stdin);
    freopen(file"out","w",stdout);
#endif // ONLIN

    cin >> n >> k;

    string s;
    cin >> s;

    for (int i = 1; i <= n; ++i)
        if (s[i-1] == 'Y')
            t[i] = 1;
        else if (s[i-1] == 'N')
            t[i] = 2;
        else if (s[i-1] == '?')
            t[i] = 3;

    int res = 0;
    for (int i = 1; i <= n; ++i)
        if (i == 1 || t[i-1] == 1 || t[i-1] == 3)
    {
        int j = i+k-1;
        if (j == n || t[j+1] == 1 || t[j+1] == 3)
            if (ok(i,j))
                res = 1;
    }

    cout<<(res ? "YES" : "NO");
}

#include <bits/stdc++.h>
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define pb push_back
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x),end(x)

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
ll const inf = 1e9;
ll const mod = 1e9 + 7;
ld const eps = 1e-9;

int main()
{
        int n, k;
        cin >> n >> k;
        string s;
        cin >> s;
        int c = 0;
        int best = 0;
        int cnt[n];
        fr(i, 0, n){
                cnt[i] = 0;
                if(i > 0) cnt[i] = cnt[i - 1];
                if(s[i] == 'N') c ++;
                else{
                        best = max(best, c);
                        c = 0;
                        if(s[i] == 'Y') cnt[i] ++;
                }
        }
        best = max(best, c);
        if(best > k){
                cout << "NO" << endl;
                return 0;
        }
        if(best == k){
                cout << "YES" << endl;
                return 0;
        }
        fr(i, 0, n - k + 1){
                if(i > 0 && s[i - 1] == 'N') continue;
                if(i + k < n && s[i + k] == 'N') continue;
                int p = 0;
                if(i > 0) p = cnt[i - 1];
                if(cnt[i + k - 1] == p){
                        cout << "YES" << endl;
                        return 0;
                }
        }
        cout << "NO"<<endl;
        return 0;
}

#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <vector>

#define ll long long
#define pb push_back
using namespace std;

int main() {
	int n,k;
	scanf("%d%d", &n, &k);
	char s[105];
	scanf("%s", &s);
	s[n] = 'Y';
	int t,mx = 0;
	for (int i=0;i<n;++i)
	{
		t = 0;
		while(i<n && s[i]=='N')
		{
			t++;
			i++;
		}
		if (t>k)
		{
			cout<<"NO";
			return 0;
		}
		if (t>mx)
			mx = t;
		if (t!=0)
			i--;
	}
	if (mx==k)
	{
		cout<<"YES";
		return 0;
	}

//	cout<<mx<<endl;

	int j = -1;
	for (int i=0;i<n;++i)
	{
		//cout<<i<<endl;
		t = 0;
		while(s[i]=='?' || s[i]=='N')
		{
			if (s[i]=='?' && j==-1)
				j = i;
			t++;
			i++;
			if (t==k)
			{
				if (s[i]=='N')
					break;
				else
				{
					cout<<"YES";
					return 0;
				}
			}
		}
		if (j!=-1)
		{
			i = j;
			j = -1;
		}
	}
cout<<"NO";
return 0;
}

#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <vector>
#include <set>
#include <string>
#include <map>
#include <algorithm>
#include <memory.h>

using namespace std;
long long MOD = 1000000007;
string go;
int sost[101][101];
int k;
int din (int pos, int least)
{
	if (sost[pos][least] != -1)
		return sost[pos][least];
	int ma = -1e9;
	if (pos == 0)
	{
		if (least == 1 && (go[0] == 'N' || go[0] == '?'))
			return 1;

		if (least == 0 && go[0] == 'N')
			return -1e9;

		if (least == 0 && (go[0] == 'Y' || go[0] == '?'))
			return 1;
	}
	if (go[pos] == 'N' && least == 0)
		return -1e9;

	if (least == 0 && (go[pos] == '?' || go[pos] == 'Y'))
		ma = max(ma, din(pos - 1, k))+1;

	if (least != 0 && go[pos] == '?')
	{
		ma = max(ma, din(pos - 1, least - 1));
		ma = max(ma, din(pos - 1, k));
	}
	if (least != 0 && go[pos] == 'N')
	{
		ma = max(ma, din(pos - 1, least - 1));
	}
	if (go[pos] == 'Y')
	{
		ma = max(ma, din(pos - 1, k));
	}
	sost[pos][least] = ma;
	return ma;
}
int main()
{
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#else
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
#endif
	int n;
	memset(sost, -1, sizeof(sost));
	cin >> n >> k;
	cin >> go;
	if (din(n - 1, k) > 0)
		puts("YES");
	else
		puts("NO");
	return 0;
}

#include <iostream>

using namespace  std;

int main(){
	int n, k;
	cin >> n >> k;
	string s;
	cin >> s;
	int min = 0;
	for (int i = 0; i<n; i++){
	    if (s[i] == 'N'){
	        int c = 0;
	        while ((i < n) && (s[i] == 'N')){
	            i++;
	            c++;
	            if (min < c)
	                min = c;
	        }
	    }
	}
	if (k < min){
	    cout << "NO";
	    return 0;
	}
	for (int i = 0; i <= n-k; i++){
	    if ((i > 0) && (s[i-1] == 'N'))
	        continue;
	    bool f = true;
	    for (int j = 0; j < k; j++)
	        if (s[i+j] == 'Y')
	            f = false;
	    if ((i+k < n) && (s[i+k] == 'N'))
	        f = false;
	    if (f){
	        cout << "YES";
	        return 0;
	    }
	}
	cout << "NO";
	return 0;
}

#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <vector>
#include <set>
#include <string>
#include <map>
#include <algorithm>
#include <memory.h>

using namespace std;
long long MOD = 1000000007;
string go;
int sost[101][101];
int k;
int din (int pos, int least)
{
	if (sost[pos][least] != -1)
		return sost[pos][least];
	int ma = -1e9;
	if (pos == 0)
	{
		if (least == 1 && (go[0] == 'N' || go[0] == '?'))
			return 1;

		if (least == 0 && go[0] == 'N')
			return -1e9;

		if (least == 0 && go[0] == 'Y')
			return 1;
	}
	if (go[pos] == 'N' && least == 0)
		return -1e9;

	if (least == 0 && (go[pos] == '?' || go[pos] == 'Y'))
		ma = max(ma, din(pos - 1, k))+1;

	if (least != 0 && go[pos] == '?')
	{
		ma = max(ma, din(pos - 1, least - 1));
		ma = max(ma, din(pos - 1, k));
	}
	if (least != 0 && go[pos] == 'N')
	{
		ma = max(ma, din(pos - 1, least - 1));
	}
	if (go[pos] == 'Y')
	{
		ma = max(ma, din(pos - 1, k));
	}
	sost[pos][least] = ma;
	return ma;
}
int main()
{
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#else
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
#endif
	int n;
	memset(sost, -1, sizeof(sost));
	cin >> n >> k;
	cin >> go;
	if (din(n - 1, k) > 0)
		puts("YES");
	else
		puts("NO");
	return 0;
}

#include <iostream>

using namespace std;

int main()
{
    bool f;
    int n,m,i,c,mx;
    string s, s2;
    cin >> n >> m;
    cin >> s;
    for (int i = 0; i < n - m + 1; i++) {
        c = 0;
        mx = 0;
        f = false;
        s2 = s;
        for (int j = i; j <= i + m - 1; j++ ) {
            if (s2[j] == 'Y') {
                f = true;
                break;
            }
        }
        if (!f) {
            for (int j = i; j <= i + m - 1; j++ ) {
                s2[j] = 'N';
            }
            for (int j = 0; j < n; j++) {
                if (s2[j] == 'N') {
                    c++;
                    if (c > mx) {
                        mx = c;
                    }
                }
                else {
                    c = 0;
                }
            }
            if (mx == m) {
                cout << "YES";
                return 0;
            }
        }
    }
    cout << "NO";
    return 0;
}

//http://codeforces.com/problemset/problem/774/J

#include <iostream>
#include <string>
#include <cmath>
#include <vector>
#include <algorithm>
#include <iterator>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <iomanip>
#include <fstream>

using namespace std;

typedef pair <int, int> pii;
typedef pair <long long, long long> pll;
typedef long long ll;
typedef unsigned long long ull;

#define endl "\n"
#define mp make_pair

const int mod = 1000000007;
const int INF = 1000000000;

int n, k, sum[105];
string result = "NO";

int get(int l, int r);

int main() {
	string str;

	ios::sync_with_stdio(false);
	cin.tie(NULL);

	cin >> n >> k >> str;

	for (int i = 0; i < n; i++) {
		if (str[i] == 'Y')
			sum[i] = 105;
		else if (str[i] == 'N')
			sum[i] = 1;
	}

	for (int i = 1; i < n; i++)
		sum[i] += sum[i - 1];

	for (int i = 0; i < n; i++) {
		int j = i + k - 1;

		if (j >= n)
			break;

		if ((get(i, j) <= k) && ((i == 0) || (str[i - 1] != 'N')) && ((j == n - 1) || (str[j + 1] != 'N')))
			result = "YES";
	}

	for (int i = 0; i < n; i++) {
		int j = i + k;

		if (j >= n)
			break;

		if (get(i, j) == k + 1)
			result = "NO";
	}

	cout << result << endl;

	return 0;
}

int get(int l, int r) {
	if (l == 0)
		return sum[r];

	return sum[r] - sum[l - 1];
}

#include <bits/stdc++.h>
using namespace std;
#define ll long long
int main()
{
    ll n,k;
    cin>>n>>k;
    string s;
    cin>>s;
    for(ll i=0;i<s.length();i++)
    {
        string t = s;
        for(ll j=0;j<s.length();j++)
        {
            if(j>=i && j<i+k && s[j]=='?')
            {
                t[j] = 'N';
            }

        }
        ll ans = 0, cnt=0;
        for(ll j=0;j<s.length();j++)
        {
            if(t[j]=='N')
            {
                cnt++;
            }
            else{
                cnt=0;
            }
            ans = max(ans, cnt);
        }
        if(ans == k)
        {
            cout<<"YES"<<endl;
            return 0;
        }
    }
    cout<<"NO"<<endl;
}

#include <bits/stdc++.h>
#define rep(i,a,b) for(int i = a; i <=b ;i++)
using namespace std;

int main()
{
    //freopen("in.txt","r",stdin);
    int n,k; cin >> n >> k; char a[101];
    rep(i,1,n) cin >> a[i]; a[n+1] = 'Y';
    rep(i,1,n) if (a[i] == 'N')
    {
        int j = i;
        while (a[j+1] == 'N') j++;
        if (j - i + 1 > k) return cout << "NO",0;
        j = i;
    }
    if (k == 0) return cout << "YES",0;
    rep(i,1,n) if (a[i] == 'N' || a[i] == '?')
    {
        int j = i;
        while (a[j+1] == 'N' || a[j+1] == '?') j++;
        if (j - i + 1 == k) return cout << "YES",0;
        rep(x,i,j - k + 1) if (a[x-1]!='N' && a[x+k]!='N'   ) return cout << "YES",0;
        i = j;
    }
    return cout << "NO",0;
}

#include <iostream>
#include <string>

using namespace std;

int main()
{
	int n, k;
	cin >> n >> k;

	string s;
	cin >> s;

	int cnt = 0;

	for (int i = 0; i < n; i++) {
		cnt = (s[i] == 'N') ? cnt + 1 : 0;
		if (cnt > k) {
			cout << "NO";
			return 0;
		}
	}

	for (int i = 0; i <= n - k; ) {
		int j = i;
		while (j < n && s[j] != 'Y')
			j++;
		int cnt_y = j;

		if (j - i == k) {
			cout << "YES";
			return 0;
		}

		for (j = i; j <= cnt_y - k; j++) {
			if ((j == 0 || s[j - 1] != 'N') && (j + k == n || s[j + k] != 'N')) {
				cout << "YES";
				return 0;
			}
		}
		i = cnt_y + 1;
	}

	cout << "NO";
}

#include <bits/stdc++.h>

using namespace std;

string s;

int main() {
 int n, k;
 cin >> n >> k >> s;
 s = "Y" + s + "Y";
queue<int> q; int d = 0; int mn = 0; int ok = 0;
 for(int i = 0; i <= n+1; i++) {
  while(q.size() && i - q.front() - 1 > k) q.pop();
  if(s[i] != 'N') {
   if(q.size() && i - q.front() - 1 == k) ok = 1;
   d = 0;
   if(s[i] == 'Y') while(q.size()) q.pop();
   q.push(i);
  }
  else mn = max(mn, ++d);
 }
 if(ok && mn <= k) cout << "YES" << endl;
 else cout << "NO" << endl;
}

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
int dp[110][110][110];
int n,m;
char a[110];
int func(int here, int ch, int ch1) {
	if (here == n) {
		if (ch1 == m)return 1;
		else return 0;
	}
	int &ret = dp[here][ch][ch1];
	if (ret != -1)return ret;
	ret = 0;
	if (a[here] == 'N')
		ret = func(here + 1, ch + 1, max(ch + 1, ch1));
	else if (a[here] == 'Y')
		ret = func(here + 1, 0, ch1);
	else
	{
		ret = max(func(here + 1, ch + 1, max(ch + 1, ch1)), func(here + 1, 0, ch1));
	}
	return ret;
}
int main()
{
	memset(dp, -1, sizeof(dp));
	scanf("%d %d", &n,&m);
	for (int i = 0; i < n; i++)
		scanf(" %1c", &a[i]);
	if (func(0, 0, 0))
		puts("YES");
	else
		puts("NO");
}

#include "bits/stdc++.h"

using namespace std;

// M A F I A - M A F I A - M A F I A - M A F I A - M A F I A - M A F I A //

#define int                                       long long
#define lop(i,s,e)                                for(int i=s;i<(int)e;i++)
#define rlop(i,e,s)                               for(int i=e;i>=s;i--)
#define prvec(v)                                  lop(R15,0,v.size())cout << v[R15] <<" "; cout << endl;
#define prarr(arr,s1,e1)                          lop(R15,s1,e1)cout << arr[R15] << " "; cout << endl;

#define endl                                      '\n'
#define ff                                        first
#define ss                                        second
#define pii                                       pair<int,int>

#define pb                                        push_back
#define vi                                        vector<int>
#define vpii                                      vector< pii >

#define all(v)                                    v.begin(),v.end()
#define sz(re)                                    (int)re.size()
#define mset(a,f)                                 memset(a,f,sizeof(a))
#define M                                         1000000007
#define Think_Twice_Code_Once                     ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)

bool J27 = 1;
#define bug(...)                                  __f (#__VA_ARGS__, __VA_ARGS__)
#define rtn                                       if(!J27)return;
template <typename Arg1>
void __f (const char* name, Arg1&& arg1) { rtn cout << name << " : " << arg1 << endl; }
template <typename Arg1, typename... Args>
void __f (const char* names, Arg1&& arg1, Args&&... args)
{     rtn
     const char* comma = strchr (names + 1, ',');
     cout.write (names, comma - names) << " : " << arg1 << " | "; __f (comma + 1, args...);
}

// M A F I A - M A F I A - M A F I A - M A F I A - M A F I A - M A F I A //

inline void INP();
const int N = 3e6 + 7;
const long long INF = LLONG_MAX;
const int inf = INT_MAX;

int n, Q, k;
int arr[N+2];

void solve()
{
      cin >> n >> k;
      string str;
      cin >> str;

      bool ans = 0;
      int mn = 0, cnt = 0;
      lop(i,0,n)
      {
            if( str[i] == 'N' ) cnt++;
            else cnt = 0;
            mn = max(mn, cnt);
      }
      if( cnt == 0 and k == 0 ) ans = 1;

      lop(i,0,n)
      {
            if( (str[i] != 'Y') and  (i == 0 or str[i-1] != 'N') )
            {
                  bool f = 1;
                  int j = 0;
                  while( i + j < n and j <= k and str[i+j] != 'Y') j++;
                  if( j > k ) j--;
                  if( j < k ) f = 0;

                  if( i + j < n and str[i+j] == 'N' ) f = 0;
                  if( f ) ans = 1;
                  bug(i,j,f,ans);
            }
      }

      bug(mn);
      if( mn <= k and ans ) cout << "YES" << endl;
      else cout << "NO" << endl;
}

int32_t main()
{

      J27 = 0;
      Think_Twice_Code_Once;
      INP();
      int t = 1;
      //cin >> t;
      while(t--) solve();

}

inline void INP()
{
      #ifndef ONLINE_JUDGE
          freopen("input.txt",  "r",  stdin);
          freopen("output.txt", "w", stdout);
      #endif
}

// M A F I A - M A F I A - M A F I A - M A F I A - M A F I A - M A F I A //

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD = 1e9+7;
int count(string s){
    s.push_back('?');
    int ans = 0, cur = 0;
    for(int i = 0; i < s.size(); ++i)
        if(s[i] == 'N')
            cur++;
        else{
            ans = max(ans,cur);
            cur = 0;
        }
    return ans;
}
int small(string s){
    for(char &c : s)
        if(c == '?')
            c = 'Y';
    return count(s);
}
bool match(string a, string b){
    for(int i = 0; i < a.size(); ++i)
        if(!(b[i] == a[i] || b[i] == '?'))
            return false;
    return true;
}
int main(){
    int n,k;
    cin >> n >> k;
    string s;
    cin >> s;
    if(small(s) > k){
        puts("NO");
        return 0;
    }
    s = 'Y' + s + 'Y';
    string req = "Y" + string(k,'N') + "Y";
    for(int i = 0; i < (int)s.size()-k+1; ++i)
        if(match(req,s.substr(i,k+2))){
            puts("YES");
            return 0;
        }
    puts("NO");
}

#include <iostream>
#include <fstream>
#include <cstdio>
#include <queue>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <stack>
#include <cstring>
#include <cmath>

#define MN 1000010
#define INF 2147483647
#define PI 3.14159265359
#define pairr pair<int, int>
#define pairrr pair<int, pairr>
#define f first
#define s second
#define pb push_back
#define ll long long
#define MOD 10000007
#define IO ios_base::sync_with_stdio(false); cin.tie();
#define PQT pairr
#define PQL priority_queue<PQT, vector<PQT>, less<PQT> >
#define PQG priority_queue<PQT, vector<PQT>, greater<PQT> >

using namespace std;

int n,k,i,t,ans=-1;
string s;

void f(int i, int t)
{
    if (i==n || t>k || t+n-i<k)
    {
        if (t==k)
        {
            cout<<"YES\n";
            exit(0);
        }
        return;
    }
    if (s[i]=='Y')
    {
        if (t==k)
        {
            cout<<"YES\n";
            exit(0);
        }
        f(i+1,0);
        return;
    }
    if (s[i]=='N')
    {
        f(i+1,t+1);
        return;
    }
    if (t==k)
    {
        cout<<"YES\n";
        exit(0);
    }
    f(i+1,0);
    f(i+1,t+1);
}

int main()
{
    IO
//    freopen("input.txt","r",stdin);
//    freopen("output.txt","w",stdout);
    cin>>n>>k>>s;
    for (i=0;i<n;i++)
    {
        if (s[i]=='N') t++;
        else
        {
            if (t>k)
            {
                cout<<"NO\n";
                exit(0);
            }
            t=0;
        }
    }
    if (t>k)
    {
        cout<<"NO\n";
        exit(0);
    }
    t=0;
    f(0,0);
    cout<<"NO\n";
    return 0;
}

#include <iostream>
#include <fstream>
#include <string>
#include <queue>

using namespace std;

void clean(queue<int>& q)
{
	while (!q.empty())
		q.pop();
}

bool processNegative(int& currentNegative, queue<int>& questions,
	int&i, int k)
{
	++currentNegative;

	if (currentNegative > k)
	{
		if (!questions.empty())
		{
			i = questions.front();
			clean(questions);
			currentNegative = 0;
		}
		else
		{
			cout << "NO" << endl;
			return false;
		}
	}

	return true;
}

int main()
{
	//ifstream cin("input.txt");

	int n, k;
	string str;
	cin >> n >> k >> str;

	str += "Y";

	auto currentNegative = 0;
	auto hadResult = false;

	queue<int> questions;

	for (auto i = 0; i < str.size(); i++)
	{
		switch (str[i])
		{
		case 'Y':
			if (currentNegative == k)
				hadResult = true;

			currentNegative = 0;
			clean(questions);
			break;
		case 'N':
			if (!processNegative(currentNegative, questions, i, k))
				return 0;
			break;
		case '?':
			if (currentNegative == k)
				hadResult = true;

			questions.push(i);
			if (!processNegative(currentNegative, questions, i, k))
				return 0;
			break;
		}
	}

	cout << (hadResult ? "YES" : "NO");
}

// Author : Sarthak Kapoor
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#define rep(i,n) for(int i=0;i<n;++i)
#define repa(i,a,n) for(int i=a;i<n;++i)
#define repr(i,n) for(int i=n-1;i>=0;--i)
#define repba(i,b,a) for(int i=b;i>=a;--i)
#define repab(i,a,b) for(int i=a;i<b;++i)
#define ll long long
#define pi pair<int,int>
#define pii pair<pi,int>
#define ull unsigned long long
#define vi vector<int>
#define viip vector<pair<int,pair<int,int> > >
#define mp make_pair
#define vip vector<pair<int,int> >
#define pb push_back
#define fi first
#define sec second
#define all(v) v.begin(),v.end()
#define s(v) v.size()
ll mod = 1000000007;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());//use rng()%n for numbers in range [0,n-1]
ll gcd(ll a,ll b){
	if(b==0)return a;
	return gcd(b,a%b);
}
ll fastexp(ll x,ll a){
    ll res = 1;
    while(a>0){
        if(a&1){
            res = (res*x)%mod;
        }
        a=a>>1;
        x=(x*x)%mod;
    }
    return res;
}
ll inverse(ll n){
    return fastexp(n,mod-2);
}
template <typename T>
void add(T &a, T b){
	a += b;
	if(a >= mod)a -= mod;
}
template <typename T>
void sub(T &a, T b){
	a -= b;
	if(a < 0)a += mod;
}
template <typename T>
void mul(T &a, T b){
	a *= b;
	if(a >= mod)a %= mod;
}
int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,k;
	cin>>n>>k;
	string s;
	cin>>s;
	// int a = 0;
	int flag = 0;
	rep(i,n){
		int j = i+k-1;
		if(j >= n)break;
		int f = 0;
		repa(k,i,j+1){
			if(s[k] == 'Y'){
				// if(i == 2){
				// 	cout<<k<<"\n";
				// }
				f = 1;
				break;
			}
		}
		// if(i == 2){
		// 	cout<<f<<"\n";
		// }
		if(f == 0){
			if(i > 0 && s[i-1] == 'N'){
				// cout<<i<<"\n";
				continue;
			}
			if(j < n-1 && s[j+1] == 'N'){
				// cout<<i<<"\n";
				continue;
			}
			flag = 1;
			break;
		}
	}
	int a = 1;
	rep(i,n){
		int j = i+k;
		if(j >= n)break;
		int f = 0;
		repa(k,i,j+1){
			if(s[k] == '?' || s[k] == 'Y'){
				f = 1;
				break;
			}
		}
		if(f == 0){
			// cout<<i<<"\n";
			a = 0;
			break;
		}
	}
	// cout<<a<<"\n";
	if(a == 1 && flag == 1){
		cout<<"YES\n";
	}
	else{
		cout<<"NO\n";
	}
	return 0;
}

#include<iostream>;
using namespace std;

int main() {
    int n, k;
    string s;
    cin >> n >> k;
    cin >> s;
    int a = 0;
    int max = 0;
    for (int i = 0; i < n; i++) {
        if (s[i] == 'N') {
            a++;
            if (max < a) {
                max = a;
            }
        } else {
            if (max < a) {
                max = a;
            }
           a = 0;
        }
    }
    if (max > k) {
        cout << "NO";
        return 0;
    }
    for (int i = 0; i < n - k + 1; i++) {
        if (i > 0 && s[i - 1] == 'N') {
            continue;
        }
        bool b = true;
        for (int j = i; j < i + k; j++) {
            if (s[j] == 'Y') {
                b = false;
                break;
            }
        }
        if (b && (i + k == n || s[i + k] != 'N')) {
            cout << "YES";
            return 0;
        }
    }
    cout << "NO";
    return 0;
}

#include <iostream>
#include <stdio.h>
#include <cmath>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <deque>
#include <stack>
#include <string>
#include <bitset>
using namespace std;

#define in(s) freopen(s, "r", stdin);
#define out(s) freopen(s, "w", stdout);
#define forn(i, n) for (int i = 0; i < n; i++)
#define endl '\n'

typedef long long ll;
typedef long double ld;

int main()
{
	//in("cakes.in");
	//out("cakes.out");
	srand(1373737);
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int n, k;
	cin >> n >> k;

	string s;
	cin >> s;

	int p = 0, len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			p++;
		}
		len = max(len, now);
	}
	if (len > k)
	{
		cout << "NO";
		return 0;
	}
	if (k == 0)
	{
		cout << "YES";
		return 0;
	}
	vector <bool> fix(n);
	forn(i, n)
	{
		if (s[i] == '?')
			s[i] = 'N';
		else
			fix[i] = true;
	}
	p = 0; len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0, start = p;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			if (now == k)
			{
				if ((start - 1 < 0 || (!fix[start - 1] && s[start - 1] == 'N' || s[start - 1] == 'Y')) && (p + 1 >= n || (!fix[p + 1] && s[p + 1] == 'N' || s[p + 1] == 'Y')))
				{
					cout << "YES";
					return 0;
				}
				else
				{
					now--;
					start++;
				}
			}
			p++;
		}
	}
	cout << "NO";
	return 0;
}

#include <bits/stdc++.h>
using namespace std;
int main() {
    int n,k; string s; cin>>n>>k>>s; bool flag = false;
    for(int i = k; i <= n; ++i) {
        string t = s;
        for(int j = 1; j <= i-k; ++j)
            if(t[j-1] == '?') t[j-1] = 'Y';
        for(int j = i+1; j <= n; ++j)
            if(t[j-1] == '?') t[j-1] = 'Y';
        for(int j = i-k+1; j <= i; ++j)
            if(t[j-1] == '?') t[j-1] = 'N';
        int c = 0, m = 0;
        for(int i = 1; i <= n; ++i) {
            if(t[i-1] == 'N') ++c;
            else {
                m = max(m,c);
                c = 0;
            }
        }
        m = max(m,c);
        if(m == k) {
            flag = true;
            break;
        }
    }
    if(flag) cout<<"YES\n";
    else cout<<"NO\n";
}

#include <iostream>
#include <algorithm>
#include <string>

using namespace std;

int main() {
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    int mx = 0, cur = 0;
    for (int i = 0; i < n; ++i) {
        if (s[i] != 'N') {
            mx = max(mx, cur);
            cur = 0;
        } else {
            ++cur;
        }
    }
    mx = max(mx, cur);
    if (mx > k) {
        cout << "NO\n";
        return 0;
    }
    int Y = 0;
    for (int i = 0; i < k; ++i) {
        Y += (s[i] == 'Y');
    }
    if (Y == 0 && (k >= n || s[k] != 'N')) {
        cout << "YES\n";
        return 0;
    }
    for (int r = k; r < n; ++r) {
        if (s[r - k] == 'Y') {
            --Y;
        }
        if (s[r] == 'Y') {
            ++Y;
        }
        if (Y == 0 && (s[r - k] != 'N' && (r + 1 >= n || s[r + 1] != 'N'))) {
            cout << "YES\n";
            return 0;
        }
    }
    cout << "NO\n";
    return 0;
}

#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <list>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cassert>
#include <ctime>
#include <cctype>
#include <cstring>
#include <bitset>
#include <algorithm>
#include <iomanip>

#define ld long double
#define ll long long
#define ull unsigned long long
#define pb push_back
#define mp make_pair
#define fst first
#define snd second
#define y0 _y0
#define y1 _y1

using namespace std;

template < typename T > T abs(T x)
{
    return x > 0 ? x : -x;
}

template < typename T > T sqr(T x)
{
    return x * x;
}

bool dp[105][105][105];

int main()
{
	int n, k;
	string s;

	cin >> n >> k;
	cin >> s;

	s.pb('Y');
	n++;

	dp[0][0][0] = 1;

	for (int i = 0; i < n; i++)
		for (int gap = 0; gap <= n; gap++)
			for (int mx = 0; mx <= n; mx++) {
				if (!dp[i][gap][mx]) continue;
				if (s[i] == 'Y') {
					dp[i + 1][0][max(mx, gap)] = 1;
				}
				if (s[i] == 'N') {
					dp[i + 1][gap + 1][mx] = 1;
				}
				if (s[i] == '?') {
					dp[i + 1][0][max(mx, gap)] = 1;
					dp[i + 1][gap + 1][mx] = 1;
				}
			}

	bool ans = dp[n][0][k];

	cout << (ans ? "YES" : "NO") << "\n";

    return 0;
}

#include <bits/stdc++.h>

using namespace std;

int main()
{
    long long n, k;
    string s;
    cin >> n >> k;
    cin >> s;
    long long t = 0;
    for(long long i = 0, cur = 1; i < n; i++, cur++){
        if(s[i] != 'N') cur = 0;
        t = max(t, cur);
    }
    if(t > k){
        cout << "NO";
        return 0;
    }
    s = "Y" + s;
    s = s + "Y";
    for(int l = 1, r = l + k - 1; r <= n; l++, r++){
        if(s[l - 1] != 'N' && s[r + 1] != 'N'){
            bool ans = 1;
            for(int i = l; i <= r; i++) ans = min(ans, !(s[i] == 'Y'));
            if(ans){
                cout << "YES";
                return 0;
            }
        }
    }
    cout << "NO";
    return 0;
}

#include <bits/stdc++.h>
#define ll long long int
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define MOD 1000000007
#define pii pair<int,int>
#define large_int 2139062143
#define large_long_long_int 9187201950435737471
using namespace std;

#define NOV 100005

int check(string s){
	for(char c:s){
		if(c=='Y')
			return 0;
	}
	return 1;
}

int getmax(string s){
	int cnt = 0,mxcnt = 0;
	for(char c:s){
		if(c=='N'){
			cnt++;
			mxcnt = max(mxcnt, cnt);
		}
		else
			cnt = 0;
	}
	return mxcnt;
}

int main(){
	ios_base::sync_with_stdio(false);
	int n,k;
	cin>>n>>k;

	string s;
	cin>>s;
	int p = getmax(s);

	if( p > k)
	{
		cout<<"NO\n";
		return 0;
	}

	vector<string> v;

	for(int i=0;i<=n-k;i++){
		if(i>0)
			if(s[i-1]=='N')
				continue;
		if(i+k<n)
			if(s[i+k] == 'N')
				continue;
		v.pb(s.substr(i,k));
	}

	for(string st:v){
		if(check(st))
		{
			cout<<"YES\n";
			return 0;
		}
	}
	cout<<"NO\n";
}

#include <bits/stdc++.h>

using namespace std;

int f(string s) {
	int res = 0;
	int cur = 0;
	for(int i = 0; i < s.size(); i++)
		if(s[i] == 'N')
			cur++;
		else {
			res = max(res, cur);
			cur = 0;
		}
	return max(res, cur);
}

int main() {
	int n, k;
	string s;
	cin >> n >> k >> s;
	for(int i = 0; i < n; i++) {
		string b = s;
		for(int j = 0; j < i; j++)
			if(b[j] == '?')
				b[j] = 'Y';
		for(int j = i; j < i + k; j++)
			if(b[j] == '?')
				b[j] = 'N';
		for(int j = i + k; j < n; j++)
			if(b[j] == '?')
				b[j] = 'Y';
		if(f(b) == k) {
			cout << "YES";
			return 0;
		}
	}
	cout << "NO";
}

#include <cstdlib>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <fstream>
#include <list>
#include <string>
#include <vector>
#include <sstream>
#include <set>
#include <queue>
#include <stack>
#include <map>
#include <cmath>
#include <functional>

typedef long long long64;
typedef long long int64;
using namespace std;

int main()
{
    //freopen("input.txt", "r", stdin);

		int n;
		int k;
		cin >> n >> k;

	    string a;
	    cin >> a;
bool no=false;
for(int i=0; i<a.size(); i++)
{
    if(a[i]=='N' && (i+k)<=a.size() && (i==0 || a[i-1]!='N'))
    {
       int count=0;
       int j;
       for(j=i; j<i+k; j++)
        {
            //cout << a[j];
            if(a[j]=='N')
                count ++;
            else
                break;
        }
        //cout << endl;
        if(count==k && j<a.size() && a[j]=='N')
        {
            cout << "NO";
            return 0;
        }
    }
}
for(int i=0; i<a.size(); i++)
{
	if((i+k)<=a.size() && (i==0 || a[i-1]!='N'))
    {
       int count=0;
       int j;
       for(j=i; j<i+k; j++)
        {
            //cout << a[j];
            if(a[j]=='?' || a[j]=='N')
                count ++;
            else
                break;
        }
        //cout << endl;
        if(count==k && (i+k==a.size() || a[j]!='N'))
        {
            cout << "YES";
            return 0;
        }
    }
}

    cout << "NO";

	return 0;
}

#include<bits/stdc++.h>

#define mp make_pair
#define pb push_back
#define forn(i, n) for (int i = 0; i < n; i++)
#define for1(i, n) for (int i = 1; i <= n; i++)
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define X first
#define Y second
#define y1 matveylox

using namespace std;

const int N = 400001;
const ll MAXN = (ll)1e6 + 7;
const int INF = (int)1e7;
const ll LINF = (ll)1e18;
const ll MOD = (ll)1e6 + 7;
const double eps = 0.00000000001;

int main()
{
    //freopen("input1.txt", "r", stdin);
    //freopen("cubes.out", "w", stdout);
    int n, v;
    string s;
    cin >> n >> v;
    cin >> s;
    forn(i, v + 1)
        s += "#";
    s = "#" + s;
    int k = 0;
    int ansk = 0, ansc = 0;
    forn(i, s.size())
    {
        if (s[i] == 'N')
            k++;
        else
        {
            ansk = max(ansk, k);
            k = 0;
        }
    }
    if (v < ansk)
        cout << "NO", exit(0);
    for(int i = 1; i <= n; i++)
    {
        bool f = true;
        for(int j = i; j < i + v; j++)
            if (s[j] == 'Y' || s[j] == '#')
                f = false;
        if (f)
            if (s[i - 1] != 'N' && s[i + v] != 'N')
                cout << "YES", exit(0);
    }
    cout << "NO";
    return 0;
}

#include <stdio.h>

int main() {
    int n, k;
    char str[1000];
    scanf("%d %d",&n, &k);
    scanf("%s", str);

    int maxC = 0;
    int tc = 0;
    for (int i = 0; i < n; i++) {
        if (str[i] == 'N') {
            tc++;
            maxC = tc > maxC ? tc : maxC;
        } else {
            tc = 0;
        }
    }

    if (maxC > k) {
        printf("NO");
        return 0;
    }

    for (int i = 0; i < n; i++) {
        int matching = 0;
        for (int j = 0; j < k; j++) {
            if (i + j >= n) {
                break;
            }
            if (str[i + j] == 'Y') {
                break;
            }
            if (str[i + j] == '?' || str[i + j] == 'N') {
                matching += 1;
            }
        }
        if (i - 1 >= 0 && str[i - 1] == 'N') {
            matching -= 1;
        }
        if (i + k < n && str[i + k] == 'N') {
            matching -= 1;
        }
        if (matching == k) {
            // printf("%d\n", i);
            printf("YES");
            return 0;
        }
    }
    printf("NO");
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
#define LL long long
#define pa pair<int,int>
const int Maxn=110;
const int inf=2147483647;
int read()
{
	int x=0,f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9')x=(x<<3)+(x<<1)+(ch^48),ch=getchar();
	return x*f;
}
int n,k;char s[Maxn];
bool f[Maxn][Maxn][Maxn];
//到i 最长为j 延伸l
int main()
{
	memset(f,false,sizeof(f));
	n=read(),k=read();
	scanf("%s",s+1);
	f[0][0][0]=true;
	for(int i=0;i<n;i++)
	for(int j=0;j<=k;j++)
	for(int l=0;l<=i;l++)
	if(f[i][j][l])
	{
		if(s[i+1]=='?')
		{
			f[i+1][max(j,l+1)][l+1]=true;
			f[i+1][j][0]=true;
		}
		else if(s[i+1]=='N')f[i+1][max(j,l+1)][l+1]=true;
		else f[i+1][j][0]=true;
	}
	for(int i=0;i<=n;i++)if(f[n][k][i])return puts("YES"),0;
	puts("NO");
}

#include <algorithm>
#include <vector>
#include <iostream>
#include <queue>
#include <cmath>

using namespace std;

int main() {
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    int cnt = 0, cntmax = 0;
    if (n == k) {
        for (int i = 0; i < n; i++) {
            if (s[i] == 'Y') {
                cout << "NO" << endl;
                return 0;
            }
        }
    }
    if (s[0] == 'N') {
        cnt = 1;
    }
    for (int i = 1; i < n; i++) {
        if (s[i] == 'N') {
            cnt++;
        } else {
            if (cntmax < cnt) {
                cntmax = cnt;
            }
            cnt = 0;
        }
    }
    if (cntmax < cnt) {
        cntmax = cnt;
    }
    if (cntmax > k) {
        cout << "NO" << endl;
        return 0;
    }
    for (int i = 1; i < n - k; i++) {
        bool flag = 0;
        for (int j = 0; j < k; j++) {
            if (s[i + j] == 'Y') {
                flag = 1;
                break;
            }
        }
        if ((s[i + k] == 'Y' || s[i + k] == '?') && (s[i - 1] == 'Y' || s[i - 1] == '?') && !flag) {
            cout << "YES" << endl;
            return 0;
        }
    }
    bool flag = 0;
    for (int i = 0; i < k; i++) {
        if (s[i] == 'Y') {
            flag = 1;
            break;
        }
    }
    if (flag == 0 && s[k] != 'N') {
        cout << "YES" << endl;
        return 0;
    }
    flag = 0;
    for (int i = n - k; i < n; i++) {
        if (s[i] == 'Y') {
            flag = 1;
            break;
        }
    }
    if (flag == 0 && s[n - k - 1] != 'N') {
        cout << "YES" << endl;
        return 0;
    }
    cout << "NO" << endl;
}

#include <bits/stdc++.h>
using namespace std;

int n, k;
char a[105];
bool vis[105][105][105];
bool memo[105][105][2];

bool dp(int i, int x, int flag) {
    if (x < 0) return false;
    if (i == -1) return (x == 0 || flag);
    if (vis[i][x][flag]) return memo[i][x][flag];
    vis[i][x][flag] = true;
    if (x == 0) flag = true;
    if (a[i] == 'N') return memo[i][x][flag] = dp(i-1, x-1, flag);
    else if (a[i] == 'Y') return memo[i][x][flag] = dp(i-1, k, flag);
    else return memo[i][x][flag] = (dp(i-1, x-1, flag) || dp(i-1, k, flag));
}

int main() {
    //freopen("in.txt", "r", stdin);
    scanf("%d%d", &n, &k);
    for (int i = 0; i < n; ++i) scanf(" %c", &a[i]);
    memset(vis, 0, sizeof vis);
    printf("%s\n", dp(n-1, k, 0) ? "YES" : "NO");
}

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define SET(x, a) memset(x, a, sizeof x);
#define mp make_pair
#define pb push_back
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define pld pair<ld, ld>
const ll MOD = 1000000007;
const ll INF = 1000000000;
template <class T> inline void read(T &x) {
  char c;
  int flag = 1;
  while ((c = getchar()) < '0' || c > '9')
    if (c == '-')
      flag *= -1;
  x = c - '0';
  while ((c = getchar()) >= '0' && c <= '9')
    x = x * 10 + c - '0';
  x *= flag;
  return;
}
bool dp[105][105];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, k;
  cin >> n >> k;
  string x;
  cin >> x;
  x = "#" + x;
  dp[0][0] = 1;
  int cnt = 0;
  int mx = 0;
  for (int i = 1; i <= n; ++i) {
    if (x[i] == 'Y' || x[i] == '?')
      cnt = 0;
    else if (x[i] == 'N')
      cnt++;
    mx = max(mx, cnt);
  }
  if (mx > k)
    return cout << "NO" << endl, 0;
  for (int i = 1; i <= n; ++i) {
    if (x[i] == 'Y' || x[i] == '?') {
      if (dp[i - 1][k])
        return cout << "YES" << endl, 0;
      dp[i][0] = 1;
    }
    if (x[i] == 'N' || x[i] == '?') {
      for (int j = 0; j < n; ++j)
        dp[i][j + 1] |= dp[i - 1][j];
    }
  }
  cout << (dp[n][k] ? "YES" : "NO") << endl;
}

#include <bits/stdc++.h>

using namespace std;

#define mp make_pair
#define pb push_back
#define makeunique(x) sort(all(x)), (x).resize(unique(x) - (x).begin())
#define re return
#define fi first
#define se second
#define sz(x) ((int) (x).size())
#define all(x) (x).begin(), (x).end()
#define sqrt(x) sqrt(abs(x))
#define y0 y3487465
#define y1 y8687969
#define j0 j5743892
#define j1 j542893

typedef vector<int> vi;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef double D;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<string> vs;
typedef vector<vi> vvi;

template<class T> T abs(T x) { re x > 0 ? x : -x; }
template<class T> T gcd(T a, T b) { re a ? gcd (b % a, a) : b; }
template<class T> T sqr(T a) { re a * a; }
template<class T> T sgn(T a) { re a > 0 ? 1 : (a < 0 ? -1 : 0); }

#define filename ""

int n;
int m;

const int N = 101;
bool was[N][N][N], ans;
char s[N];

void go (int i, int j, int k)
{
	if (i == n) {
		ans |= k == m;
		re ;
	}
	if (was[i][j][k]) re ;
	if (s[i] == 'N') go (i + 1, j + 1, max(j + 1, k));
	else if (s[i] == 'Y') go (i + 1, 0, k);
	else if (s[i] == '?') go (i + 1, 0, k), go (i + 1, j + 1, max(j + 1, k));
	was[i][j][k] = true;
	re ;
}

int main () {
//	freopen (filename".in", "r", stdin);
//	freopen (filename".out", "w", stdout);
	scanf ("%d%d ", &n, &m);
	gets (s);
	go (0, 0, 0);
	if (ans) puts ("YES");
	else puts("NO");

	return 0;
}

#include<bits/stdc++.h>
 using namespace std;

 int n, k, i, j, ans,val,l,mx = 0;
 string s;

 int main(){

    cin >> n >> k;
    cin >> s;

    for(i=0;i<s.size();++i){
        if(s[i]=='N'){
            ++ans;
            if(ans>k) return cout<<"NO\n",0;
            mx=max(mx,ans);
        } else{
            ans = 0;
        }
    }

    if(mx == k) return cout <<"YES\n",0;

    for(i = 0; i < s.size(); ++i)
    for(j = i; j < s.size(); ++j){
            val  = 0;
            int mx = 0;
        for(l = 0; l < s.size(); ++l)
        if(s[l] == 'N'){
            ++val;
        } else{
        if(s[l]=='?'){
            if(l>=i && l<=j){
                ++val;
            }
           else {
            mx=max(mx,val);
            val = 0;
        }
        } else{
            mx=max(mx,val);
            val = 0;
        }
    }
    mx=max(mx,val);
    if(mx==k)return cout<<"YES\n",0;
    }

    return cout << "NO\n", 0;

 }

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

int main(){

    //Stepan's Series

    int i, n, k, prev, now, ans;
    string s;

    cin>>n>>k;
    cin>>s;

    prev=0;
    ans=0;

    for (i=0;i<n;i++){
        if (s[i]=='N'){
            now=prev+1;
        }
        else {
            now=0;
        }
        prev=now;
        ans=max(ans, now);
    }

    if (ans==k){
        cout<<"YES\n";
    }
    else if (ans<k){
        int j;
        bool b=true;
        vector <int> v;
        for (i=0;i<n;i++){
            if (s[i]=='N'||s[i]=='?'){
                if (b){
                    v.push_back(i);
                    b=false;
                }
            }
            else {
                b=true;
            }
        }
        for (i=0;i<v.size();i++){
            prev=0;
            ans=0;
            for (j=v[i];j<n;j++){
                if (s[j]=='N'){
                    now=prev+1;
                }
                else if (s[j]=='?'){
                    if (ans<k){
                        now=prev+1;
                    }
                    else {
                        now=0;
                    }
                }
                else {
                    now=0;
                }
                prev=now;
                ans=max(ans, now);
            }
            if (ans==k){
                break;
            }
        }
        if (ans==k){
            cout<<"YES\n";
        }
        else {
            cout<<"NO\n";
        }
    }
    else {
        cout<<"NO\n";
    }

    return 0;
}

#include "bits/stdc++.h"

using namespace std;

// M A F I A - M A F I A - M A F I A - M A F I A - M A F I A - M A F I A //

#define int                                       long long
#define lop(i,s,e)                                for(int i=s;i<(int)e;i++)
#define rlop(i,e,s)                               for(int i=e;i>=s;i--)
#define prvec(v)                                  lop(R15,0,v.size())cout << v[R15] <<" "; cout << endl;
#define prarr(arr,s1,e1)                          lop(R15,s1,e1)cout << arr[R15] << " "; cout << endl;

#define endl                                      '\n'
#define ff                                        first
#define ss                                        second
#define pii                                       pair<int,int>

#define pb                                        push_back
#define vi                                        vector<int>
#define vpii                                      vector< pii >

#define all(v)                                    v.begin(),v.end()
#define sz(re)                                    (int)re.size()
#define mset(a,f)                                 memset(a,f,sizeof(a))
#define M                                         1000000007
#define Think_Twice_Code_Once                     ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)

bool J27 = 1;
#define bug(...)                                  __f (#__VA_ARGS__, __VA_ARGS__)
#define rtn                                       if(!J27)return;
template <typename Arg1>
void __f (const char* name, Arg1&& arg1) { rtn cout << name << " : " << arg1 << endl; }
template <typename Arg1, typename... Args>
void __f (const char* names, Arg1&& arg1, Args&&... args)
{     rtn
     const char* comma = strchr (names + 1, ',');
     cout.write (names, comma - names) << " : " << arg1 << " | "; __f (comma + 1, args...);
}

// M A F I A - M A F I A - M A F I A - M A F I A - M A F I A - M A F I A //

inline void INP();
const int N = 3e6 + 7;
const long long INF = LLONG_MAX;
const int inf = INT_MAX;

int n, Q, k;
int arr[N+2];

void solve()
{
      cin >> n >> k;
      string str;
      cin >> str;

      bool ans = 0;
      int mn = 0, cnt = 0;
      lop(i,0,n)
      {
            if( str[i] == 'N' ) cnt++;
            else cnt = 0;
            mn = max(mn, cnt);
      }

      lop(i,0,n)
      {
            if( (str[i] != 'Y') and  (i == 0 or str[i-1] != 'N') )
            {
                  bool f = 1;
                  int j = 0;
                  while( i + j < n and j <= k and str[i+j] != 'Y') j++;
                  if( j > k ) j--;
                  if( j < k ) f = 0;

                  if( i + j < n and str[i+j] == 'N' ) f = 0;
                  if( j == k and f ) ans = 1;
                  bug(i,j,f,ans);
            }
      }

      if( mn <= k and ans ) cout << "YES" << endl;
      else cout << "NO" << endl;
}

int32_t main()
{

      J27 = 0;
      Think_Twice_Code_Once;
      INP();
      int t = 1;
      //cin >> t;
      while(t--) solve();

}

inline void INP()
{
      #ifndef ONLINE_JUDGE
          freopen("input.txt",  "r",  stdin);
          freopen("output.txt", "w", stdout);
      #endif
}

// M A F I A - M A F I A - M A F I A - M A F I A - M A F I A - M A F I A //

#include <algorithm>
#include <vector>
#include <iostream>
#include <map>
#include <fstream>
#include <set>
#include <queue>
#include <cmath>
#define all(x) x.begin(), x.end()

using namespace std;
typedef long long ll;

int main() {
	cin.tie(0), cout.tie(0), ios_base::sync_with_stdio(0);
	string s;
	int n, k;
	cin >> n >> k >> s;
	s = s + '8';
	vector<int>pr(s.size() + 1, 0), pp(s.size() + 1, 0);
	for (int i = s.size() - 2; i >= 0; --i) {
		if (s[i] == 'N')pp[i] = pp[i + 1] + 1;
		if (s[i] != 'Y')pr[i] = pr[i + 1] + 1;
		//cout << i << ": \n";
		//cout << "chain: " << pr[i] << "\n";
		//cout << "have n: " << pp[i] << "\n";
	}
	bool ok = 0;
	for (int i = 0; i < s.size(); ++i) {
		if (pr[i] >= k && s[i + k] != 'N') {
			if (i > 0 && s[i - 1] != 'N' || i == 0) {
				ok = 1;
				cout << i << " " << pr[i]<<"\n";
			}
		}
	}
	for (int i = 0; i < s.size() - 1; i++) {
		if (pp[i] > k) {
			cout << "NO"; exit(0);
		}
	}
	if (ok)cout << "YES";
	else cout << "NO";
	return 0;
}/*
 12 2 N?N

 12 2 YYYYYN?N

 0 6
 N??NN?NNY

 0 7
 N??NN??NY

 */

#include <iostream>
#include <string>

using namespace std;

int main()
{
	int n, k;
	cin >> n >> k;

	string s;
	cin >> s;

	int cnt = 0;

	for (int i = 0; i < n; i++) {
		cnt = (s[i] == 'N') ? cnt + 1 : 0;
		if (cnt > k) {
			cout << "NO";
			return 0;
		}
	}

	for (int i = 0; i < n - k; i++) {
		int j = i;
		while (j < n && s[j] != 'Y')
			j++;
		int cnt_y = j;

		if (j - i == k) {
			cout << "YES";
			return 0;
		}

		for (j = i; j < cnt_y - k; j++) {
			if ((j == 0 || s[j - 1] == '?') && (j + k == n || s[j + k] == '?')) {
				cout << "YES";
				return 0;
			}
		}
	}

	cout << "NO";
}

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
char a[250];
int main()
{
    int n,k;
    scanf("%d%d",&n,&k);
    getchar();
    for(int i=1; i<=n; i++)
    {
        scanf("%c",&a[i]);
    }
    // printf("%s",a);
    int p=1,kk,maxx=0,flag=0;
    for(int i=1; i<=n; i+=p)
    {
        //printf("i=%d\n",i);
        if(a[i]=='N')
        {
            kk=0;
            for(int j=i; j<=n; j++)
            {
                if(a[j]=='N')
                {
                    kk++;
                }
                else
                {
                    p=kk;
                    break;
                }
            }
            maxx=max(maxx,kk);
            int kkk=kk;
          //  printf("%d\n",kk);
            if(kk<k)
            {
                for(int j=i-1; j>=1; j--)
                {
                    if((a[j]=='?'&&j==1)||(a[j]=='?'&&a[j-1]!='N'))
                    {
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                        kk++;
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                    }
                    else if(a[j]=='?'&&a[j-1]=='N')
                    {
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                        kk++;
                    }
                    else if(a[j]=='N')
                        kk++;
                    else if(a[j]=='Y')
                    {
                        break;
                    }
                }
                if(flag==0)
                {
                    for(int j=i+p; j<=n; j++)
                    {
                        if((a[j]=='?'&&j==n)||(a[j]=='?'&&a[j+1]!='N'))
                        {
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kkk++;
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                        }
                        else if(a[j]=='?'&&a[j+1]=='N')
                        {
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kkk++;
                        }
                        else if(a[j]=='N')
                            kkk++;
                        else if(a[j]=='Y')
                        {
                            break;
                        }
                    }
                }

            }
         //   printf("%d %d %d\n",i,kk,kkk);

            //  maxx=max(maxx,kkk);
        }
        else
        {
            p=1;
        }
    }
    //printf("%d\n",maxx);
    if(maxx==k||(maxx<k&&flag))
        printf("YES\n");
    else printf("NO\n");
}

#include<bits/stdc++.h>
 using namespace std;

 int n, k, i, j, ans,val,l;
 string s;

 int main(){

    cin >> n >> k;
    cin >> s;

    for(i=0;i<s.size();++i){
        if(s[i]=='N'){
            ++ans;
            if(ans>k) return cout<<"NO\n",0;
        } else{
            ans = 0;
        }
    }

    for(i = 0; i < s.size(); ++i)
    for(j = i; j < s.size(); ++j){
            val = 0;
        for(l = 0; l < s.size(); ++l)
        if(s[l] == 'N'){
            ++val;
        } else{
        if(s[l]=='?'){
            if(l>=i && l<=j){
                ++val;
            }
           else {
            if(val == k) return cout << "YES\n",0;
            val = 0;
        }
        } else{
            if(val == k) return cout << "YES\n",0;
            val = 0;
        }
    }
    if(val == k) return cout << "YES\n",0;
    }

    return cout << "NO\n", 0;

 }

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
char a[250];
int main()
{
    int n,k;
    scanf("%d%d",&n,&k);
    getchar();
    for(int i=1; i<=n; i++)
    {
        scanf("%c",&a[i]);
    }
    // printf("%s",a);
    int p=1,kk,maxx=0,flag=0,kkk,sum=0;
    for(int i=1; i<=n; i+=p)
    {
        //printf("i=%d\n",i);
        if(a[i]=='N')
        {
            kk=0;
            for(int j=i; j<=n; j++)
            {
                if(a[j]=='N')
                {
                    kk++;
                }
                else
                {
                    p=kk;
                    break;
                }
            }
            maxx=max(maxx,kk);
             kkk=kk;
            //  printf("%d\n",kk);
            if(kk<k)
            {
                for(int j=i-1; j>=1; j--)
                {
                    if((a[j]=='?'&&j==1)||(a[j]=='?'&&a[j-1]!='N'))
                    {
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                        kk++;
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                    }
                    else if(a[j]=='?'&&a[j-1]=='N')
                    {
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                        kk++;
                    }
                    else if(a[j]=='N')
                        kk++;
                    else if(a[j]=='Y')
                    {
                        break;
                    }
                }
                if(flag==0)
                {
                    for(int j=i+p; j<=n; j++)
                    {
                        if((a[j]=='?'&&j==n)||(a[j]=='?'&&a[j+1]!='N'))
                        {
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kkk++;
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                        }
                        else if(a[j]=='?'&&a[j+1]=='N')
                        {
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kkk++;
                        }
                        else if(a[j]=='N')
                            kkk++;
                        else if(a[j]=='Y')
                        {
                            break;
                        }
                    }
                }

            }
            //   printf("%d %d %d\n",i,kk,kkk);

            //  maxx=max(maxx,kkk);
        }
        else
        {
            sum++;
            p=1;
        }
    }
    if(sum==n)
    {
        kk=0;
        for(int i=1;i<=n;i++)
        {
            if(a[i]=='?')
            {
                if(kk==k)
                {
                    flag=1;
                    break;
                }
                kk++;
                if(kk==k)
                {
                    flag=1;
                    break;
                }
            }
            else
            {
                kk=0;
            }
        }
    }
   // printf("%d\n",flag);
    if(maxx==k||(maxx<k&&flag))
        printf("YES\n");
    else printf("NO\n");
}

//#include <bits/stdc++.h>
#include <iostream>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <vector>
#include <deque>
#include <stack>
#include <fstream>
#include <cmath>
#include <cassert>
using namespace std;

#define MOD 1000000007

vector<uint64_t> factors(uint64_t x) {
    set<uint64_t> fac;
    vector<uint64_t> space;
    for (uint64_t i = 1; i <= uint64_t(sqrt(x)); i++) {
        if (x % i == 0) {
            fac.insert(x / i);
            fac.insert(i);
        }
    }

    for (auto& y : fac) {
        space.push_back(y);
    }
    return space;
}

int main() {
	std::ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);

	uint64_t n, k;
	cin >> n>> k;
    string s;
    cin >> s;
    int maxi = 0;
    int curr = 0;
    for (int i = 0; i < s.size(); i++) {
        if (s[i] == 'N') {
            curr++;
        }
        else {
            maxi = max(maxi, curr);
            curr = 0;
        }
    }
    maxi = max(maxi, curr);
    if (maxi > k) {
        cout << "NO" << endl;
        return 0;
    }
    else {
        if (maxi == k) {
            cout << "YES" << endl;
            return 0;
        }
        else {
            for (int i = 0; i <= s.size()-k; i++) {
                bool valid = true;
                if (i > 0 && s[i - 1] == 'N') continue;
                for (int j = 0; j < k; j++) {
                    if (s[i + j] == 'Y') {
                        valid = false;
                        break;
                    }
                }
                if (valid) {
                    if (i + k < s.size() && s[i + k] != 'N') {
                        cout << "YES" << endl;
                        return 0;
                    }
                }
            }
            cout << "NO" << endl;
            return 0;
        }
    }

	return 0;
}

#include <iostream>
#include <string>

using namespace std;

int main()
{
	int n, k;
	cin >> n >> k;

	string s;
	cin >> s;

	int cnt = 0;

	for (int i = 0; i < n; i++) {
		cnt = (s[i] == 'N') ? cnt + 1 : 0;
		if (cnt > k) {
			cout << "NO";
			return 0;
		}
	}

	for (int i = 0; i < n - k; ) {
		int j = i;
		while (j < n && s[j] != 'Y')
			j++;
		int cnt_y = j;

		if (j - i == k) {
			cout << "YES";
			return 0;
		}

		for (j = i; j < cnt_y - k; j++) {
			if ((j == 0 || s[j - 1] == '?') && (j + k == n || s[j + k] == '?')) {
				cout << "YES";
				return 0;
			}
		}
		i = cnt_y + 1;
	}

	cout << "NO";
}

#include <iostream>

using namespace std;

int main()
{
	int n, k, a = 0, nowmin = 0, nowmax = 0, min = 2147483647, max = 0, f = 1;
	cin >> n >> k;
	char* s = new char[n];
	cin >> s;

	for (a = 0; a < n; a++)
	{
		if (s[a] != 'Y') { nowmax++; if (max < nowmax) max++; }
		else nowmax = 0;
		if (s[a] == 'N') nowmin++;
		else { if ((nowmin != 0) & (min > nowmin)) { min = nowmin; } nowmin = 0; }
	}
	if ((s[a - 1] == 'N') & (min > nowmin)) min = nowmin;
	if (min == 2147483647) min = 0;
	if (k > max) { cout << "NO"; return 0; }
	if ((k == min) | (k == max)) { cout << "YES"; return 0; }
	if (k < min) { cout << "NO"; return 0; }

	n -= k;
	for (a = 0; a < n; a++)
	{
		for (int b = a; b < a + k; b++)
		{
			if (s[b] == 'Y') { f = 0; break; }
		}
		if (f)
		{
			if (a + k == n - 1) { cout << "YES"; return 0; }
			else if (s[a + k + 1] != 'N') f = 1;
			else f = 1;
		}
		else f = 1;
	}
	cout << "NO";
	return 0;
}

#include <iostream>
#include <fstream>
#include <string>
#include <queue>

using namespace std;

void clean(queue<int>& q)
{
	while (!q.empty())
		q.pop();
}

bool processNegative(int& currentNegative, queue<int>& questions,
	int&i, int k)
{
	++currentNegative;

	if (currentNegative > k)
	{
		if (!questions.empty())
		{
			i = questions.front();
			clean(questions);
			currentNegative = 0;
		}
		else
		{
			cout << "NO" << endl;
			return false;
		}
	}

	return true;
}

int main()
{
	// ifstream cin("input.txt");

	int n, k;
	string str;
	cin >> n >> k >> str;

	auto currentNegative = 0;
	auto hadResult = false;

	queue<int> questions;

	for (auto i = 0; i < n; i++)
	{
		switch (str[i])
		{
		case 'Y':
			if (currentNegative == k)
				hadResult = true;

			currentNegative = 0;
			clean(questions);
			break;
		case 'N':
			if (!processNegative(currentNegative, questions, i, k))
				return 0;
			break;
		case '?':
			if (currentNegative == k)
				hadResult = true;

			questions.push(i);
			if (!processNegative(currentNegative, questions, i, k))
				return 0;
			break;
		}
	}

	cout << (hadResult ? "YES" : "NO");
}

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
char a[250];
int main()
{
   int n,k;
   scanf("%d%d",&n,&k);
   getchar();
   for(int i=0;i<n;i++)
   {
       scanf("%c",&a[i]);
       a[i+n]=a[i];
   }
  // printf("%s",a);
   int p=1,kk,maxx=0;
   for(int i=0;i<2*n;i+=p)
   {
       if(a[i]=='N')
       {
           kk=0;
           for(int j=i;j<2*n;j++)
           {
               if(a[j]=='N')
               {
                    kk++;
               }
                else
                {
                    p=j-i;
                    break;
                }
           }
          // printf("%d\n",i);
           maxx=max(maxx,kk);
       }
   }
   if(maxx>k)
   printf("NO\n");
   else printf("YES\n");
}

//#include <bits/stdc++.h>
#include <iostream>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <vector>
#include <deque>
#include <stack>
#include <fstream>
#include <cmath>
#include <cassert>
using namespace std;

#define MOD 1000000007

vector<uint64_t> factors(uint64_t x) {
    set<uint64_t> fac;
    vector<uint64_t> space;
    for (uint64_t i = 1; i <= uint64_t(sqrt(x)); i++) {
        if (x % i == 0) {
            fac.insert(x / i);
            fac.insert(i);
        }
    }

    for (auto& y : fac) {
        space.push_back(y);
    }
    return space;
}

int main() {
	std::ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);

	uint64_t n, k;
	cin >> n>> k;
    string s;
    cin >> s;
    int maxi = 0;
    int curr = 0;
    for (int i = 0; i < s.size(); i++) {
        if (s[i] == 'N') {
            curr++;
        }
        else {
            maxi = max(maxi, curr);
            curr = 0;
        }
    }
    if (curr > k) {
        cout << "NO" << endl;
        return 0;
    }
    else {
        if (curr == k) {
            cout << "YES" << endl;
            return 0;
        }
        else {
            for (int i = 0; i <= s.size()-k; i++) {
                bool valid = true;
                for (int j = 0; j < k; j++) {
                    if (s[i + j] == 'Y') {
                        valid = false;
                        break;
                    }
                }
                if (valid) {
                    if (i + k < s.size() || s[i + k] != 'N') {
                        cout << "YES" << endl;
                        return 0;
                    }
                }
            }
            cout << "NO" << endl;
            return 0;
        }
    }

	return 0;
}

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int MAXN = 2e5 + 5;
const long long MOD = 1e9 + 7;

int main()
{
	//freopen("input.in","r",stdin);
    //freopen("output.out","w",stdout);

	int n,k; cin >> n >> k;
	string s; cin >> s;
	int c1 = 0; int c2 = 0;
	for(int i = 0; i < n;)
	{
		if(s[i] == 'N')
		{
			int j = i;
			while(j < n && s[j] == 'N')
				j++;
			c1 = max(c1,j - i);
			i = j;
		}
		else
		{
			i++;
		}
	}
	for(int i = 0; i < n;)
	{
		if(s[i] == 'N' || s[i] == '?')
		{
			int j = i;
			while(j < n && (s[j] == 'N' || s[j] == '?'))
				j++;
			c2 = max(c2,j - i);
			i = j;
		}
		else
		{
			i++;
		}
	}
	if(c1 > k || c2 < k){
		cout << "NO";
		return 0;
	}
	else
	{
		cout << "YES\n";
	}
	return 0;

}

#include <cstdlib>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <fstream>
#include <list>
#include <string>
#include <vector>
#include <sstream>
#include <set>
#include <queue>
#include <stack>
#include <map>
#include <cmath>
#include <functional>

typedef long long long64;
typedef long long int64;
using namespace std;

int main()
{
    //freopen("input.txt", "r", stdin);

		int n;
		int k;
		cin >> n >> k;

	    string a;
	    cin >> a;
bool no=false;
for(int i=0; i<a.size(); i++)
{
    if(a[i]=='N' && (i+k)<=a.size() && (i==0 || a[i-1]!='N'))
    {
       int count=0;
       int j;
       for(j=i; j<i+k; j++)
        {
            //cout << a[j];
            if(a[j]=='N')
                count ++;
            else
                break;
        }
        //cout << endl;
        if(count==k && j<a.size() && a[j]=='N')
        {
            cout << "NO";
            return 0;
        }
    }
}
for(int i=0; i<a.size(); i++)
{
	if((a[i]=='N' || a[i]=='?') && (i+k)<=a.size() && (i==0 || a[i-1]!='N'))
    {
       int count=0;
       int j;
       for(j=i; j<i+k; j++)
        {
            //cout << a[j];
            if(a[j]=='?' || a[j]=='N')
                count ++;
            else
                break;
        }
        //cout << endl;
        if(count==k && (i+k==a.size() || a[j]!='N'))
        {
            cout << "YES";
            return 0;
        }
    }
}

    cout << "NO";

	return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <ctime>
#include <cmath>
#include <string>
#include <stdlib.h>
#include <fstream>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <deque>
#include <iterator>
#include <iomanip>
#include <climits>
#include <numeric>
#include <cstring>
#include <list>
using namespace std;
#define ll long long int

const int MAXN = 2e5 + 1;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n, k;
    string s;
    cin >> n >> k >> s;

    int cnt = 0, a = 0;

    for(int i = 0; i < n; ++i){
        if(s[i] == 'N'){
            if(i && s[i - 1] == 'N') cnt++;
            else cnt = 1;
        }
        if(s[i] != 'N') cnt = 0;

        a = max(a, cnt);
    }

    if(a > k){
        cout << "NO\n";
        return 0;
    }

    for(int i = 0; i <= n - k; ++i){
        bool ok = true;
        if(i && s[i - 1] == 'N') continue;
        if(i + k != n - 1 && s[i + k + 1] == 'N') continue;
        for(int j = i; j < i + k; ++j){
            if(s[j] == 'Y'){
                ok = false;
                break;
            }
        }

        if(ok){
            cout << "YES\n";
            return 0;
        }
    }

    cout << "NO\n";
}

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <algorithm>

using namespace std;

int main(){

    //Stepan's Series

    int i, n, k, prev, now, ans;
    string s;

    cin>>n>>k;
    cin>>s;

    prev=0;
    ans=0;

    for (i=0;i<n;i++){
        if (s[i]=='N'){
            now=prev+1;
        }
        else {
            now=0;
        }
        prev=now;
        ans=max(ans, now);
    }

    if (ans==k){
        cout<<"YES\n";
    }
    else if (ans<k){
        int j;
        for (i=0;i<n-k;i++){
            prev=0;
            ans=0;
            for (j=i;j<n;j++){
                if (s[j]=='N'){
                    now=prev+1;
                }
                else if (s[j]=='?'){
                    if (ans<k){
                        now=prev+1;
                    }
                    else {
                        now=0;
                    }
                }
                else {
                    now=0;
                }
                prev=now;
                ans=max(ans, now);
            }
            if (ans==k){
                break;
            }
        }
        if (ans==k){
            cout<<"YES\n";
        }
        else {
            cout<<"NO\n";
        }
    }
    else {
        cout<<"NO\n";
    }

    return 0;
}

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <cstring>
#include <string>
#include <vector>
#define MIN 1<<31-1
#define REP(i,n) for(int i = 0; i < (n); i++)
typedef long long int ll;
char NN[10000];
int zu[10000];
using namespace std;
int main()
{
	int n,k,l,r;
	cin>>n>>k;
	l=0;r=0;
	int flag=0;
	int nowl=0;
	int cou=0;
	for(int i=0;i<n;i++)
	{
		cin>>NN[i];
	}
	int i;
	for(i=0;i<n;i++)
	{
		if((NN[i]=='N'||NN[i]=='?')&&NN[i-1]!='N')
		{
			int w;
			for(w=1;w<k;w++)
				if(w+i>=n||NN[w+i]=='Y')
					break;
			if(w==k&&NN[i+w+1]!='N')
			{
				break;
			}
		}
	}
	int out=0;
	if(i!=n)
		out=1;
	int mi=0;
	int nmi=0;
	for(i=0;i<n;i++)
	{
		if(NN[i]=='N')
		{
			nmi++;
		}
		else
		{
			mi=max(mi,nmi);
			nmi=0;
		}
	}
	if(out==1&&mi<=k)
		cout<<"YES";
	else
		cout<<"NO";
	return 0;
}

#include <bits/stdc++.h>
using namespace std;

// IIT se hain BC!  //

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int n,k;
	cin>>n>>k;
	char str[n+1];
	cin>>str;
	bool flag=true;
	for (int i = 0; i < n-k; ++i){
		int count=0;
		bool flag1=false;
		bool flag2=false;
		for (int j = 0; j < k; ++j){
			if(str[i+j]!='Y')
				count+=1;
		}
		if(count==k){
			flag=true;
			if(i>0&&str[i-1]=='N'){
				flag=false;
				break;
			}
			if(i<n-k-1&&str[i+k]=='N'){
				flag=false;
				break;
			}
		}
	}
	if(flag)
		cout<<"YES"<<endl;
	else
		cout<<"NO"<<endl;

	return 0;
}

#include <iostream>
#include <algorithm>
#include <string>

using namespace std;

int main() {
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    int mx = 0, cur = 0;
    for (int i = 0; i < n; ++i) {
        if (s[i] != 'N') {
            mx = max(mx, cur);
            cur = 0;
        } else {
            ++cur;
        }
    }
    mx = max(mx, cur);
    if (mx > k) {
        cout << "NO\n";
        return 0;
    }
    int Y = 0;
    for (int i = 0; i < k; ++i) {
        Y += (s[i] == 'Y');
    }
    if (Y == 0) {
        cout << "YES\n";
        return 0;
    }
    for (int r = k; r < n; ++r) {
        if (s[r - k] == 'Y') {
            --Y;
        }
        if (s[k] == 'Y') {
            ++Y;
        }
        if (Y == 0) {
            cout << "YES\n";
            return 0;
        }
    }
    cout << "NO\n";
    return 0;
}

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
char a[250];
int main()
{
   int n,k;
   scanf("%d%d",&n,&k);
   getchar();
   for(int i=0;i<n;i++)
   {
       scanf("%c",&a[i]);
       a[i+n]=a[i];
   }
  // printf("%s",a);
   int p=1,kk,maxx=0;
   for(int i=0;i<2*n;i+=p)
   {
       if(a[i]=='N')
       {
           kk=0;
           for(int j=i;j<2*n;j++)
           {
               if(a[j]=='N')
               {
                    kk++;
               }
                else
                {
                    p=j-i+1;
                    break;
                }
           }
          // printf("%d\n",kk);
           maxx=max(maxx,kk);
       }
   }
   if(maxx>k)
   printf("NO\n");
   else printf("YES\n");
}

//90 18
//NNNN?NNNNNYNYNYNNY?NNNNNNNNNNNNNNYNNNNNNYYNYYNNNNYNNNNNNNNNNNNNNNNNNNYNNYYNYNNNNNNNYNNNNYN

#include <iostream>
#include <stdio.h>
#include <cmath>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <deque>
#include <stack>
#include <string>
#include <bitset>
using namespace std;

#define in(s) freopen(s, "r", stdin);
#define out(s) freopen(s, "w", stdout);
#define forn(i, n) for (int i = 0; i < n; i++)
#define endl '\n'

typedef long long ll;
typedef long double ld;

int main()
{
	//in("cakes.in");
	//out("cakes.out");
	srand(1373737);
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int n, k;
	cin >> n >> k;

	string s;
	cin >> s;

	int p = 0, len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			p++;
		}
		len = max(len, now);
	}
	if (len > k)
	{
		cout << "NO";
		return 0;
	}
	vector <bool> fix(n);
	forn(i, n)
	{
		if (s[i] == '?')
			s[i] = 'N';
		else
			fix[i] = true;
	}
	p = 0; len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0, start = p;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			p++;
			if (now == k)
			{
				if ((start - 1 < 0 || !fix[start - 1]) && (p + 1 >= n || !fix[p + 1]))
				{
					cout << "YES";
					return 0;
				}
				else
				{
					now--;
					start++;
				}
			}
		}
	}
	cout << "NO";
	return 0;
}

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int MAXN = 2e5 + 5;
const long long MOD = 1e9 + 7;

pair<int,int> p;

int main()
{
	//freopen("input.in","r",stdin);
    //freopen("output.out","w",stdout);

	int n,k; cin >> n >> k;
	string s; cin >> s;
	int c1 = 0; int c2 = 0;
	for(int i = 0; i < n;)
	{
		if(s[i] == 'N')
		{
			int j = i;
			while(j < n && s[j] == 'N')
				j++;
			c1 = max(c1,j - i);
			i = j;
		}
		else
		{
			i++;
		}
	}
	for(int i = 0; i < n;)
	{
		if(s[i] == 'N' || s[i] == '?')
		{
			int j = i;
			while(j < n && (s[j] == 'N' || s[j] == '?'))
				j++;
			c2 = max(c2,j - i);
			i = j;
		}
		else
		{
			i++;
		}
	}
	if(c1 > k || c2 < k){
		cout << "NO";
		return 0;
	}

	for(int i = 0; i < n; ++i)
	{
		for(int j = i; j < n; ++j)
		{
			if(j - i + 1 < k) continue;
			else
			{
				int c = 0;
				for(int l = i; l <= j; ++l)
				{
					if(s[l] == '?' || s[l] == 'N')
						c++;
				}
				if(c == k){
					int fl = 1;
					if(i - 1 >= 0 && s[i] == 'Y') fl = 0;
					if(j + 1 < n && s[j] == 'Y') fl = 0;
					if(fl)
					{
						cout << "YES\n";
						return 0;
					}
				}
			}
		}
	}
	cout << "NO";

	return 0;

}

#include <iostream>

using namespace  std;

int main(){
	int n, k;
	cin >> n >> k;
	string s;
	cin >> s;
	int min = 0;
	for (int i = 0; i<n; i++){
	    if (s[i] == 'N'){
	        int c = 0;
	        while ((i < n) && (s[i] == 'N')){
	            i++;
	            c++;
	            if (min < c)
	                min = c;
	        }
	    }
	}
	if (k < min){
	    cout << "NO";
	    return 0;
	}
	for (int i = 0; i <= n-k; i++){
	    if ((i > 0) && (s[i-1] == 'N'))
	        continue;
	    bool f = true;
	    for (int j = 0; j < k; j++)
	        if (s[i+j] == 'Y')
	            f = false;
	    if ((i+k+1 < n) && (s[i+k+1] == 'N'))
	        f = false;
	    if (f){
	        cout << "YES";
	        return 0;
	    }
	}
	cout << "NO";
	return 0;
}

#include <iostream>
#include <vector>
#include <string>

using namespace std;

bool check(string &s, int k, int ind)
{
    int cntr = 0;
    for (int i = ind; i < s.size(); i++)
    {
        if (s[i] == 'N' || s[i] == '?')
        {
            cntr++;
        }
        else if (s[i] == 'Y' && cntr < k)
            return false;
        if (cntr == k)
        {
            if (i == s.size() - 1)
                return true;
            else if (s[i+1] != 'N')
                return true;
            else
                return false;
        }
    }
    return false;
}

int main()
{
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    bool ok = check(s, k, 0);
    if (ok)
    {
        cout << "YES" << endl;
        return 0;
    }
    for (int i = 1; i < s.size(); i++)
        if ((s[i] == 'N' || s[i] == '?') && s[i-1] != 'N')
        {
            ok = check(s, k, i);
            if (ok)
                break;
        }

    if (ok)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}

#include <iostream>

using namespace  std;

int main(){
	int n, k;
	cin >> n >> k;
	string s;
	cin >> s;
	int min = 0;
	for (int i=0; i<n; i++){
	    if (s[i] == 'N'){
	        int c = 0;
	        while ((i < n) && (s[i] == 'N')){
	            i++;
	            c++;
	            if (min < c)
	                min = c;
	        }
	    }
	}
	if (k < min){
	    cout << "NO";
	    return 0;
	}
	for (int i = 0; i < n-k; i++){
	    if ((i > 0) && (s[i-1] == 'N'))
	        continue;
	    bool f = true;
	    for (int j = 0; j < k; j++)
	        if (s[i+j] == 'Y')
	            f = false;
	    if ((i+k+1 < n) && (s[i+k+1] == 'N'))
	        f = false;
	    if (f){
	        cout << "YES";
	        return 0;
	    }
	}
	cout << "NO";
	return 0;
}

#include<iostream>;
using namespace std;

int main() {
    int n, k;
    string s;
    cin >> n >> k;
    cin >> s;
    int a = 0;
    int max = 0;
    for (int i = 0; i < n; i++) {
        if (s[i] == 'N') {
            a++;
            if (max < a) {
                max = a;
            }
        } else {
            if (max < a) {
                max = a;
            }
           a = 0;
        }
    }
    if (max > k) {
        cout << "NO";
        return 0;
    }
    for (int i = 0; i < n; i++) {
        if (i > 0 && s[i - 1] == 'N') {
            continue;
        }
        bool b = true;
        for (int j = i; j < i + k; j++) {
            if (s[j] == 'Y') {
                b = false;
                break;
            }
        }
        if (b && (i + k == n || s[i + k] != 'N')) {
            cout << "YES";
            return 0;
        }
    }
    cout << "NO";
    return 0;
}

#include<bits/stdc++.h>
 using namespace std;

 int n, k, i, j, ans,val,l;
 string s;

 int main(){

    cin >> n >> k;
    cin >> s;

    for(i=0;i<s.size();++i){
        if(s[i]=='N'){
            ++ans;
            if(ans>k) return cout<<"NO\n",0;
        } else{
            ans = 0;
        }
    }

    for(i = 0; i < s.size(); ++i)
    for(j = i; j < s.size(); ++j){
            val = 0;
        for(l = 0; l < s.size(); ++l)
        if(s[l] == 'N'){
            ++val;
        } else{
        if(s[l]=='?'){
            if(l>=i && l<=j){
                ++val;
            }
           else {
            if(val == k) return cout << "YES\n",0;
            val = 0;
        }
        } else{
            if(val == k) return cout << "YES\n",0;
            val = 0;
        }
    }
    if(val == k) return cout << "YES\n",0;
    }

    return cout << "NO\n", 0;

 }

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int MAXN = 2e5 + 5;
const long long MOD = 1e9 + 7;

pair<int,int> p;

int main()
{
	//freopen("input.in","r",stdin);
    //freopen("output.out","w",stdout);

	int n,k; cin >> n >> k;
	string s; cin >> s;
	int c1 = 0; int c2 = 0;
	for(int i = 0; i < n;)
	{
		if(s[i] == 'N')
		{
			int j = i;
			while(j < n && s[j] == 'N')
				j++;
			c1 = max(c1,j - i);
			i = j;
		}
		else
		{
			i++;
		}
	}
	for(int i = 0; i < n;)
	{
		if(s[i] == 'N' || s[i] == '?')
		{
			int j = i;
			while(j < n && (s[j] == 'N' || s[j] == '?'))
				j++;
			c2 = max(c2,j - i);
			i = j;
		}
		else
		{
			i++;
		}
	}
	if(c1 > k || c2 < k){
		cout << "NO";
		return 0;
	}

	for(int i = 0; i < n; ++i)
	{
		for(int j = i; j < n; ++j)
		{
			if(j - i + 1 !=  k) continue;
			else
			{
				int c = 0;
				for(int l = i; l <= j; ++l)
				{
					if(s[l] == '?' || s[l] == 'N')
						c++;
				}
				if(c == k){
					int fl = 1;
					if(i - 1 >= 0 && s[i - 1] == 'N') fl = 0;
					if(j + 1 < n && s[j + 1] == 'N') fl = 0;
					if(fl)
					{
						cout << "YES\n";
						return 0;
					}
				}
			}
		}
	}
	cout << "NO";

	return 0;

}

#include <iostream>
#include <vector>
#include <algorithm>
#include <ctime>
#include <cmath>
#include <string>
#include <stdlib.h>
#include <fstream>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <deque>
#include <iterator>
#include <iomanip>
#include <climits>
#include <numeric>
#include <cstring>
#include <list>
using namespace std;
#define ll long long int

const int MAXN = 2e5 + 1;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n, k;
    string s;
    cin >> n >> k >> s;

    int cnt = 0, a = 0;

    for(int i = 0; i < n; ++i){
        if(s[i] == 'N'){
            if(i && s[i - 1] == 'N') cnt++;
            else cnt = 1;
        }
        if(s[i] != 'N') cnt = 0;

        a = max(a, cnt);
    }

    if(a > k){
        cout << "NO\n";
        return 0;
    }

    for(int i = 0; i < n - k; ++i){
        bool ok = true;
        if(i && s[i - 1] == 'N') continue;
        int k = 0;
        if(i + k != n - 1 && s[i + k + 1] == 'N') continue;
        for(int j = i; j < i + k; ++j){
            k++;
            if(s[j] == 'Y'){
                ok = false;
                break;
            }
        }

        if(ok){
            cout << "YES\n";
            return 0;
        }
    }

    cout << "NO\n";
}

#include <bits/stdc++.h>
using namespace std;

const int N = 105;

char s[N];

bool dp[N][N][2];

bool solveDp(int ind,int cons,int g,int n,int k) {
    if(cons>k) {
        return false;
    }
    if(ind==n) {
        if(g) {
            return true;
        }
        else {
            return false;
        }
    }
    if(dp[ind][cons][g]) {
        return false;
    }
    dp[ind][cons][g] = true;
    if(s[ind]=='?') {
        int tmp = 0;
        int ng = g;
        if(tmp==k) {
            ng = 1;
        }
        if(solveDp(ind+1,tmp,ng,n,k) ){
            return true;
        }
        tmp = cons+1;
        ng = g;
        if(tmp==k) {
            ng = 1;
        }
        if(solveDp(ind+1,tmp,ng,n,k) ){
            return true;
        }
    }
    else if(s[ind]=='Y') {
        int tmp = 0;
        int ng = g;
        if(solveDp(ind+1,tmp,ng,n,k) ) {
            return true;
        }
    } else {
        int tmp = cons+1;
        int ng = g;
        if(tmp==k) {
            ng = 1;
        }
        if(solveDp(ind+1,tmp,ng,n,k) ) {
            return true;
        }
    }
    return false;
}

void solve() {
    int n,k;
    scanf("%d %d",&n,&k);
    scanf("%s",s);
    int g = 0;
    return;
    if(k==0) {
        g = 1;
    }
    if(solveDp(0,0,g,n,k)) {
        cout<<"YES\n";
    } else {
        cout<<"NO\n";
    }
}

int main()
{
    solve();
}

#include<bits/stdc++.h>
using namespace std;

#define ll       long long int
#define ull      unsigned long long int
#define pb       push_back
#define vpop     pop_back
#define mp       make_pair
#define ff       first
#define ss       second
#define clz(x)   __builtin_clz(x)       //count leading zeroes
#define ctz(x)   __builtin_ctz(x)       //count trailing zeroes
#define sbts(x)  __builtin_popcount(x) //count set bits
#define ps(x, y) fixed << setprecision(y) << x
#define all(v)   v.begin(), v.end()
#define umap	 unordered_map
const int MOD  =  1e9 + 7;
const ll INF   =  1e12;

int main() {
    // freopen("input.txt","r",stdin);
    // freopen("output.txt","w",stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n, k;
    cin >> n >> k;
    string str;
    cin >> str;
    int _maxN = 0, _maxQ = 0, N = 0, Q = 0;
    for(int i = 0; i < n; i++) {
        if(str[i] != 'N')   N = 0;
        else if(str[i] != '?')  Q = 0;
        if(str[i] == 'N')  {
            N++;    _maxN = max(_maxN, N);
        }
        else if(str[i] == '?')  {
            Q++;    _maxQ = max(_maxQ, Q);
        }
    }
    if(k == _maxN || (k > _maxN && k <= _maxQ))
        cout << "YES";
    else
        cout << "NO";
    return 0;
}

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
char a[250];
int main()
{
   int n,k;
   scanf("%d%d",&n,&k);
   getchar();
   for(int i=0;i<n;i++)
   {
       scanf("%c",&a[i]);
       a[i+n]=a[i];
   }
  // printf("%s",a);
   int p=1,kk,maxx=0,flag=0;
   for(int i=0;i<2*n;i+=p)
   {
       if(a[i]=='N')
       {
           kk=0;
           for(int j=i;j<2*n;j++)
           {
               if(a[j]=='N')
               {
                    kk++;
               }
                else
                {
                    p=j-i+1;
                    break;
                }
           }
           if(kk==k)
           {
               flag=1;
           }
          else if(kk<k)
           {
               for(int j=i-1;j>=0;j--)
               {
                   if((a[j]=='?'&&a[j-1]!='N')||(a[j]=='?'&&j==0))
                   {
                       kk++;
                       if(kk==k)
                       {
                           flag=1;
                           break;
                       }
                   }
                  else if(a[j]=='N')
                    kk++;
                    else
                        break;
               }
               if(kk==k)
               {
                   flag=1;
               }
           }
          // printf("%d\n",kk);
           maxx=max(maxx,kk);
       }
   }
   if(maxx==k)
   printf("YES\n");
   else printf("NO\n");
}

#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <vector>

#define ll long long
#define pb push_back
using namespace std;

int main() {
	int n,k;
	scanf("%d%d", &n, &k);
	char s[105];
	scanf("%s", &s);
	s[n] = 'Y';
	int t,mx = 0;
	for (int i=0;i<n;++i)
	{
		t = 0;
		while(i<n && s[i]=='N')
		{
			t++;
			i++;
		}
		if (t>k)
		{
			cout<<"NO";
			return 0;
		}
		if (t>mx)
			mx = t;
		if (t!=0)
			i--;
	}
	if (mx==k)
	{
		cout<<"YES";
		return 0;
	}

//	cout<<mx<<endl;

	int j = -1;
	for (int i=0;i<n;++i)
	{
		cout<<i<<endl;
		t = 0;
		while(s[i]=='?' || s[i]=='N')
		{
			if (s[i]=='?' && j==-1)
				j = i;
			t++;
			i++;
			if (t==k)
			{
				if (s[i]=='N')
					break;
				else
				{
					cout<<"YES";
					return 0;
				}
			}
		}
		if (j!=-1)
		{
			i = j;
			j = -1;
		}
	}
cout<<"NO";
return 0;
}

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define PI 3.1415926535
using namespace __gnu_pbds;
using namespace std;

typedef long long ll;
typedef pair <ll, ll> pll;

bool check(string &s, ll k) {
    ll cnt = 0;
    for(auto i: s) {
        if(i == 'N') cnt++;
        if(cnt > k) return false;
    }
    return true;
}

int main(){
    ios_base:: sync_with_stdio(0);
    //start();
    ll n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    if(!check(s, k)) {
        cout << "NO";
        return 0;
    }
    for(ll i = 0; i < n; i++) {
        if(s[i] == '?' || s[i] == 'N') {
            ll cnt = 0;
            while((s[i] == '?' && cnt < k)|| s[i] == 'N') {
                cnt++;
            }
            if(cnt == k) {
                cout << "YES";
                return 0;
            }
        }
    }
    cout << "NO";
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef complex<double> cplx;

#define sqr(x) ((x)*(x))
#define pb push_back
#define X first
#define Y second
#define sit(a) set<a>::iterator
#define mit(a,b) map<a,b>::iterator

const ll mod=1000000007LL;
const int inf=0x3f3f3f3f;
const int maxn=500005,maxm=10005;
const double eps=1e-10;
const double pi=acos(-1.0);

char c[maxn];
int n,k;
bool v[maxn]={0};

bool check()
{
    int i,j;
    for(i=0;i<n;i++)
    {
        for(j=i;j<i+k&&j<n&&c[j]=='N';j++);
        if(j<n&&j==i+k&&c[j]=='N') return 0;
    }
    return 1;
}

void solve()
{
    int i,j;
    for(i=0;i+k<=n;i++)
    {
        for(j=i;j<i+k&&c[j]!='Y';j++) c[j]='N';
        if(check()) {printf("YES\n");return;}
        for(j=i;j<i+k&&v[j];j++) c[j]='?';
    }
    printf("NO\n");
}

int main()
{
    int i,j;
    scanf("%d %d %s",&n,&k,c);
    for(i=0;i<n;i++) if(c[i]=='?') v[i]=1;
    solve();
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define mp make_pair
#define pb push_back
#define X first
#define Y second
#define MOD 1000000007

#define trace1(x)                    cout <<#x<<": "<<x<< endl;
#define trace2(x, y)                 cout <<#x<<": "<<x<<" | "<<#y<<": "<<y<< endl;
#define trace3(x, y, z)              cout <<#x<<": "<<x<<" | "<<#y<<": "<<y<<" | "<<#z<<": "<<z<<endl;
#define trace4(a, b, c, d)           cout <<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<endl;

typedef long long ll;

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    ll i,j,n,m,k;
    cin>>n>>k;
    string s;
    cin>>s;
    ll pos=0;
    for(i=1;i<=n-k+1;i++)
    {
        ll r=0;
        for(j=0;j<k;j++)
        {
            if(s[i+j-1]=='Y')
            {
                j=-1;
                break;
            }
            else if(s[i+j-1]=='?')
            r++;
        }
        if(j!=-1)
        {
            if(i!=1 && s[i-2]=='N' && r==0)
            {
                cout<<"NO";
                return 0;
            }
            if(i+k-1+1<=n && s[i+k-1]=='N' && r==0)
            {
                cout<<"NO";
                return 0;
            }
            pos=1;
        }
    }
    if(pos==1)
    cout<<"YES";
    else
    cout<<"NO";
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
int main() {
    int n,k; string s; cin>>n>>k>>s; bool flag = false;
    for(int i = k; i <= n; ++i) {
        string t = s;
        for(int j = 1; j <= i-k; ++j)
            if(t[j-1] == '?') t[j-1] = 'Y';
        for(int j = i; j <= n; ++j)
            if(t[j-1] == '?') t[j-1] = 'Y';
        for(int j = i-k+1; j <= i; ++j)
            if(t[j-1] == '?') t[j-1] = 'N';
        int c = 0, m = 0;
        for(int i = 1; i <= n; ++i) {
            if(t[i-1] == 'N') ++c;
            else {
                m = max(m,c);
                c = 0;
            }
        }
        if(m == k) {
            flag = true;
            break;
        }
    }
    if(flag) cout<<"YES\n";
    else cout<<"NO\n";
}

#include<bits/stdc++.h>

#define mp make_pair
#define pb push_back
#define forn(i, n) for (int i = 0; i < n; i++)
#define for1(i, n) for (int i = 1; i <= n; i++)
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define X first
#define Y second
#define y1 matveylox

using namespace std;

const int N = 400001;
const ll MAXN = (ll)1e6 + 7;
const int INF = (int)1e7;
const ll LINF = (ll)1e18;
const ll MOD = (ll)1e6 + 7;
const double eps = 0.00000000001;

int main()
{
    //freopen("input1.txt", "r", stdin);
    //freopen("cubes.out", "w", stdout);
    int n, v;
    string s;
    cin >> n >> v;
    cin >> s;
    s += "#";
    s = "#" + s;
    int k = 0;
    int ansk = 0, ansc = 0;
    forn(i, s.size())
    {
        if (s[i] == 'N')
            k++;
        else
        {
            ansk = max(ansk, k);
            k = 0;
        }
    }
    if (v < ansk)
        cout << "NO", exit(0);
    for(int i = 1; i <= n - v; i++)
    {
        bool f = true;
        for(int j = i; j < i + v; j++)
            if (s[j] == 'Y')
                f = false;
        if (f)
            if (s[i - 1] != 'N' && s[i + v] != 'N')
                cout << "YES", exit(0);
    }
    cout << "NO";
    return 0;
}

#include <iostream>
#include <algorithm>
#include <string>

using namespace std;

int main() {
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    int mx = 0, cur = 0;
    for (int i = 0; i < n; ++i) {
        if (s[i] != 'N') {
            mx = max(mx, cur);
            cur = 0;
        } else {
            ++cur;
        }
    }
    mx = max(mx, cur);
    if (mx > k) {
        cout << "NO\n";
        return 0;
    }
    int Y = 0;
    for (int i = 0; i < k; ++i) {
        Y += (s[i] == 'Y');
    }
    if (Y == 0) {
        cout << "YES\n";
        return 0;
    }
    for (int r = k; r < n; ++r) {
        if (s[r - k] == 'Y') {
            --Y;
        }
        if (s[r] == 'Y') {
            ++Y;
        }
        if (Y == 0 && (s[r - k] != 'N' && (r + 1 >= n || s[r + 1] != 'N'))) {
            cout << "YES\n";
            return 0;
        }
    }
    cout << "NO\n";
    return 0;
}

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
char a[250];
int main()
{
    int n,k;
    scanf("%d%d",&n,&k);
    getchar();
    for(int i=1; i<=n; i++)
    {
        scanf("%c",&a[i]);
    }
    // printf("%s",a);
    int p=1,kk,maxx=0,flag=0,kkk;
    for(int i=1; i<=n; i+=p)
    {
        //printf("i=%d\n",i);
        if(a[i]=='N')
        {
            kk=0;
            for(int j=i; j<=n; j++)
            {
                if(a[j]=='N')
                {
                    kk++;
                }
                else
                {
                    p=kk;
                    break;
                }
            }
            maxx=max(maxx,kk);
             kkk=kk;
            //  printf("%d\n",kk);
            if(kk<k)
            {
                for(int j=i-1; j>=1; j--)
                {
                    if((a[j]=='?'&&j==1)||(a[j]=='?'&&a[j-1]!='N'))
                    {
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                        kk++;
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                    }
                    else if(a[j]=='?'&&a[j-1]=='N')
                    {
                        if(kk>=k)
                        {
                            if(kk==k)
                            {
                                flag=1;
                            }
                            break;
                        }
                        kk++;
                    }
                    else if(a[j]=='N')
                        kk++;
                    else if(a[j]=='Y')
                    {
                        break;
                    }
                }
                if(flag==0)
                {
                    for(int j=i+p; j<=n; j++)
                    {
                        if((a[j]=='?'&&j==n)||(a[j]=='?'&&a[j+1]!='N'))
                        {
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kkk++;
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                        }
                        else if(a[j]=='?'&&a[j+1]=='N')
                        {
                            if(kkk>=k)
                            {
                                if(kkk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kkk++;
                        }
                        else if(a[j]=='N')
                            kkk++;
                        else if(a[j]=='Y')
                        {
                            break;
                        }
                    }
                }

            }
            //   printf("%d %d %d\n",i,kk,kkk);

            //  maxx=max(maxx,kkk);
        }
        else
        {
            p=1;
            if(a[i]=='?')
            {
                kk=kkk=0;
                if(kk<k)
                {
                    for(int j=i; j>=1; j--)
                    {
                        if((a[j]=='?'&&j==1)||(a[j]=='?'&&a[j-1]!='N'))
                        {
                            if(kk>=k)
                            {
                                if(kk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kk++;
                            if(kk>=k)
                            {
                                if(kk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                        }
                        else if(a[j]=='?'&&a[j-1]=='N')
                        {
                            if(kk>=k)
                            {
                                if(kk==k)
                                {
                                    flag=1;
                                }
                                break;
                            }
                            kk++;
                        }
                        else if(a[j]=='N')
                            kk++;
                        else if(a[j]=='Y')
                        {
                            break;
                        }
                    }
                    if(flag==0)
                    {
                        for(int j=i; j<=n; j++)
                        {
                            if((a[j]=='?'&&j==n)||(a[j]=='?'&&a[j+1]!='N'))
                            {
                                if(kkk>=k)
                                {
                                    if(kkk==k)
                                    {
                                        flag=1;
                                    }
                                    break;
                                }
                                kkk++;
                                if(kkk>=k)
                                {
                                    if(kkk==k)
                                    {
                                        flag=1;
                                    }
                                    break;
                                }
                            }
                            else if(a[j]=='?'&&a[j+1]=='N')
                            {
                                if(kkk>=k)
                                {
                                    if(kkk==k)
                                    {
                                        flag=1;
                                    }
                                    break;
                                }
                                kkk++;
                            }
                            else if(a[j]=='N')
                                kkk++;
                            else if(a[j]=='Y')
                            {
                                break;
                            }
                        }
                    }

                }
            }
        }
    }
    //printf("%d\n",maxx);
    if(maxx==k||(maxx<k&&flag))
        printf("YES\n");
    else printf("NO\n");
}

#include <iostream>

using namespace std;

int main()
{
	int n, k, a = 0, nowmin = 0, nowmax = 0, min = 0, max = 0, f = 1;
	cin >> n >> k;
	char* s = new char[n];
	cin >> s;

	for (a = 0; a < n; a++)
	{
		if (s[a] != 'Y') { nowmax++; if (max < nowmax) max++; }
		else nowmax = 0;
		if (s[a] == 'N') { nowmin++; if (min < nowmin) min++; }
		else nowmin = 0;
	}
	if ((s[a - 1] == 'N') & (min > nowmin)) min = nowmin;
	if (k > max) { cout << "NO"; return 0; }
	if ((k == min) | (k == max)) { cout << "YES"; return 0; }
	if (k < min) { cout << "NO"; return 0; }

	n -= k;
	for (a = 0; a < n; a++)
	{
		for (int b = a; b < a + k; b++)
		{
			if (s[b] == 'Y') { f = 0; break; }
		}
		if (f)
		{
			if (a == n - 1)
			{
				if (s[a - 1] == 'N') { cout << "NO"; return 0; }
				else { cout << "YES"; return 0; }
			}
			else if (a == 0)
			{
				if (s[a + k] == 'N') f = 1;
				else { cout << "YES"; return 0; }
			}
			else
			{
				if ((s[a - 1] != 'N') & (s[a + k] != 'N')) { cout << "YES"; return 0; }
				else f = 1;
			}
		}
		else f = 1;
	}
	cout << "NO";
	return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <ctime>
#include <cmath>
#include <string>
#include <stdlib.h>
#include <fstream>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <deque>
#include <iterator>
#include <iomanip>
#include <climits>
#include <numeric>
#include <cstring>
#include <list>
using namespace std;
#define ll long long int

const int MAXN = 2e5 + 1;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n, k;
    string s;
    cin >> n >> k >> s;

    int cnt = 0, a = 0;

    for(int i = 0; i < n; ++i){
        if(s[i] == 'N'){
            if(i && s[i - 1] == 'N') cnt++;
            else cnt = 1;
        }
        if(s[i] != 'N') cnt = 0;

        a = max(a, cnt);
    }

    if(a > k){
        cout << "NO\n";
        return 0;
    }

    for(int i = 0; i < n - k; ++i){
        bool ok = true;
        if(i && s[i - 1] == 'N') continue;
        if(i + k != n - 1 && s[i + k + 1] == 'N') continue;
        for(int j = i; j < i + k; ++j){
            if(s[j] == 'Y'){
                ok = false;
                break;
            }
        }

        if(ok){
            cout << "YES\n";
            return 0;
        }
    }

    cout << "NO\n";
}

//I read the news today, oh boy
//About a lucky man who made the grade

#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define sz(x) int((x).size())
#define all(v) (v).begin(),(v).end()
#define trace(x) cerr << #x << " = " << x << endl
#define fastio ios_base::sync_with_stdio(0);cin.tie(0)
#define For(i,a,b) for(int i = int(a); i < int(b); ++i)
#define roF(i,a,b) for(int i = int(a); i >= int(b); i--)
using namespace std;

typedef long long ll;
typedef pair<int,int> ii;

int dp[1000];
int here[1000][1000];

int solve(string s){
	memset(dp,0,sizeof(dp));
	dp[0]=(s[0]=='N');
	For(i,1,sz(s)){
		if(s[i]!='N')dp[i]=0;
		else dp[i]=dp[i-1]+1;
	}
	int mx=0;
	For(i,0,sz(s))mx=max(mx,dp[i]);
	return mx;
}

int main(){
	fastio;
	int n,k;cin>>n>>k;
	string s;cin>>s;
	int mn=solve(s);
	if(k<mn){
		cout<<"NO"<<endl;
		return 0;
	}
	For(i,0,n)if(s[i]=='?')s[i]='N';
	bool find=false;
	For(i,0,sz(s))For(tam,1,i+1){
		if(i<sz(s)-1&&s[i+1]=='N')continue;
		here[i][tam]=true;
		For(j,i-tam+1,i+1)if(s[j]=='Y')
			here[i][tam]=false;
		if(i-tam>=0&&s[i-tam]=='N')here[i][tam]=false;
		if(tam==k&&here[i][tam])find=true;
	}
	if(find)cout<<"YES"<<endl;
	else cout<<"NO"<<endl;

	return 0;
}

#include <iostream>
#include <stdio.h>
#include <cmath>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <deque>
#include <stack>
#include <string>
#include <bitset>
using namespace std;

#define in(s) freopen(s, "r", stdin);
#define out(s) freopen(s, "w", stdout);
#define forn(i, n) for (int i = 0; i < n; i++)
#define endl '\n'

typedef long long ll;
typedef long double ld;

int main()
{
	//in("cakes.in");
	//out("cakes.out");
	srand(1373737);
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int n, k;
	cin >> n >> k;

	string s;
	cin >> s;

	int p = 0, len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			p++;
		}
		len = max(len, now);
		if (now == k)
		{
			cout << "YES";
			return 0;
		}
	}
	if (len > k)
	{
		cout << "NO";
		return 0;
	}
	vector <bool> fix(n);
	forn(i, n)
	{
		if (s[i] == '?')
			s[i] = 'N';
		else
			fix[i] = true;
	}
	p = 0; len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0, start = p;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			if (now == k)
			{
				if ((start - 1 < 0 || (!fix[start - 1] && s[start - 1] == 'N' || s[start - 1] == 'Y')) && (p + 1 >= n || (!fix[p + 1] && s[p + 1] == 'N' || s[p + 1] == 'Y')))
				{
					cout << "YES";
					return 0;
				}
				else
				{
					now--;
					start++;
				}
			}
			p++;
		}
	}
	cout << "NO";
	return 0;
}

#include <iostream>
#include <stdio.h>
#include <cmath>
#include <math.h>
#include <string>
#include <algorithm>
#include <functional>
#include <stack>
#include <list>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <unordered_set>
#include <unordered_map>
#include <bitset>
#include <sstream>
#include <cassert>

#define PI 3.1415926535
#define ll long long
#define ull unsigned long long
#define umap unordered_map
#define uset unordered_set
#define all(a) a.begin(), a.end()
#pragma comment(linker, "/STACK:64777216")

using namespace std;

const int MAXINT = (int)2e9 + 100;
const ll MAXN = 100000;
const ll MAXVAL = 10000000;
const ll INF = (ll)1e18 + 50;
const ll MOD = (ll)1e9 + 7;
const ull HASH_MOD = 2305843009213693951;
string failMessage;

void fail()
{
	cout << failMessage;
	exit(0);
};

int f(string s)
{
	s += "Y";

	int max_len = -1, cur = 0;

	for (int i = 0; i < s.length(); i++)
	{
		if (s[i] != 'N')
		{
			max_len = max(max_len, cur);
			cur = 0;
		}
		else if (s[i] == 'N')
		{
			cur++;
		}
	}

	return max_len;
}

void solve()
{
	int n, k;
	cin >> n >> k;
	string s;
	cin >> s;

	int l = f(s);
	for (int i = 0; i < n; i++)
		if (s[i] == '?')
			s[i] = 'N';

	int r = f(s);

	if (k >= l && k <= r)
		cout << "YES";
	else
		cout << "NO";
}

int main()
{
	const string FILENAME = "111";
#ifndef LOCAL
	//freopen((FILENAME + ".in").data(), "r", stdin);
	//freopen((FILENAME + ".out").data(), "w", stdout);
#endif // !LOCAL

	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.precision(15);
	solve();

}

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cmath>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>

using namespace std;
typedef long long LL;
const LL INF=1e17L;
const int inf=0x3f3f3f3f;
const int maxn=1e3+5;
const int Mod=1e9+7;
int n,k;
string s;
int dp[maxn][maxn]; // dp[i][0]表示以i结尾可以构成的最短长度,dp[i][1]表示以i结尾可以构成的最长长度
/*
void init()
{

    for(int i=1;i<=n;i++)
    {
        p[i][i]=(s[i-1]=='Y')?0:1;
        for(int j=i+1;j<=n;j++)
        {
            p[i][j]=p[i][j-1]&((s[j-1]=='Y')?0:1);
        }
    }
}
*/
int main()
{

    cin>>n>>k>>s;
    //init();
    dp[0][0]=dp[0][1]=0;
    bool flag=false;
    for(int i=1;i<=n;i++)
    {
        char c=s[i-1];
        if(c=='Y')
        {
            dp[i][0]=dp[i][1]=0;
        }
        else if(c=='N')
        {
            dp[i][0]=dp[i-1][0]+1;
            dp[i][1]=dp[i-1][1]+1;
        }
        else if(c=='?')
        {
            dp[i][0]=0;
            dp[i][1]=dp[i-1][1]+1;
        }
        if(dp[i][0]>k) {flag=true;break;};
    }
    if(flag) puts("NO\n");
    else
    {
        int pos=n,t=0;
        while(pos>=1 && !t)
        {
            if(dp[pos][1]>=k) t=1;
            pos--;
        }
        if(t) puts("YES");else puts("NO");
    }
    return 0;
}

#include <iostream>
#include <fstream>
#include <cstdio>
#include <queue>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <stack>
#include <cstring>
#include <cmath>

#define MN 1000010
#define INF 2147483647
#define PI 3.14159265359
#define pairr pair<int, int>
#define pairrr pair<int, pairr>
#define f first
#define s second
#define pb push_back
#define ll long long
#define MOD 10000007
#define IO ios_base::sync_with_stdio(false); cin.tie();
#define PQT pairr
#define PQL priority_queue<PQT, vector<PQT>, less<PQT> >
#define PQG priority_queue<PQT, vector<PQT>, greater<PQT> >

using namespace std;

int n,k,i,t,z,ans=-1;
string s;

int main()
{
    IO
//    freopen("input.txt","r",stdin);
//    freopen("output.txt","w",stdout);
    cin>>n>>k;
    cin>>s;
    for (i=0;i<s.length();i++)
    {
        if (s[i]=='Y')
        {
            if (t==k)
            {
                ans=1;
                break;
            }
            if (t>k)
            {
                ans=0;
                break;
            }
            t=0;
        }
        else
        if (s[i]=='N')
        {
            t++;
        }
    }
            if (t==k)
            {
                ans=1;
            }
            if (t>k) ans=0;
    if (ans==1) cout<<"YES\n";
    else
    if (ans==0) cout<<"NO\n";
    else
    {
        t=0;
        for (i=0;i<s.length();i++)
        {
            if (s[i]=='Y')
            {
                if (t+z>=k)
                {
                    ans=1;
                    break;
                }
                t=0;
                z=0;
            }
            else
            if (s[i]=='?')
            {
                z++;
            }
            else
            {
                t++;
            }
        }
        if (ans==1) cout<<"YES\n";
        else cout<<"NO\n";
    }
    return 0;
}

//I read the news today, oh boy
//About a lucky man who made the grade

#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define sz(x) int((x).size())
#define all(v) (v).begin(),(v).end()
#define trace(x) cerr << #x << " = " << x << endl
#define fastio ios_base::sync_with_stdio(0);cin.tie(0)
#define For(i,a,b) for(int i = int(a); i < int(b); ++i)
#define roF(i,a,b) for(int i = int(a); i >= int(b); i--)
using namespace std;

typedef long long ll;
typedef pair<int,int> ii;

int dp[1000];
int here[1000][1000];

int solve(string s){
	memset(dp,0,sizeof(dp));
	dp[0]=(s[0]=='N');
	For(i,1,sz(s)){
		if(s[i]!='N')dp[i]=0;
		else dp[i]=dp[i-1]+1;
	}
	int mx=0;
	For(i,0,sz(s))mx=max(mx,dp[i]);
	return mx;
}

int main(){
	fastio;
	int n,k;cin>>n>>k;
	string s;cin>>s;
	int mn=solve(s);
	if(k<mn){
		cout<<"NO"<<endl;
		return 0;
	}
	bool find=false;
	s.pb('Y');
	For(i,0,n)For(tam,1,i+2){
		if(s[i+1]=='N')continue;
		here[i][tam]=true;
		For(j,i-tam+1,i+1)if(s[j]=='Y')
			here[i][tam]=false;
		//if(i==11&&tam==7)trace(here[i][tam]);
		if(i-tam>=0&&s[i-tam]=='N')here[i][tam]=false;
		if(tam==k&&here[i][tam])find=true;
	}
	if(find)cout<<"YES"<<endl;
	else cout<<"NO"<<endl;

	return 0;
}

#include<bits/stdc++.h>

#define mp make_pair
#define pb push_back
#define forn(i, n) for (int i = 0; i < n; i++)
#define for1(i, n) for (int i = 1; i <= n; i++)
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define X first
#define Y second
#define y1 matveylox

using namespace std;

const int N = 400001;
const ll MAXN = (ll)1e6 + 7;
const int INF = (int)1e7;
const ll LINF = (ll)1e18;
const ll MOD = (ll)1e6 + 7;
const double eps = 0.00000000001;

int main()
{
    //freopen("input1.txt", "r", stdin);
    //freopen("cubes.out", "w", stdout);
    int n, v;
    string s;
    cin >> n >> v;
    cin >> s;
    s += "#";
    int k = 0;
    int ansk = 0, ansc = 0;
    forn(i, s.size())
    {
        if (s[i] == 'N')
            k++;
        else
        {
            ansk = max(ansk, k);
            k = 0;
        }
    }
    int c = 0;
    forn(i, s.size())
    {
        if (s[i] == 'N' || s[i] == '?')
            c++;
        else
        {
            ansc = max(ansc, c);
            c = 0;
        }
    }
    //cout << ansk << ' ' << ansc;
    if (v >= min(ansk, ansc) && v <= max(ansk, ansc))
        cout << "YES";
    else
        cout << "NO";
    return 0;
}

#include <bits/stdc++.h>
#define maxn 200
using namespace std;

int n, m;
char a[maxn];

int main()
{
	scanf("%d%d", &n, &m);
	scanf("%s", a + 1);

	if(m == 0)  //特判
	{
		for(int i = 1; i <= n; ++i)
		{
			if(a[i] == 'N')
			{
				printf("NO\n");
				return 0;
			}
		}
		printf("YES\n");
		return 0;
	}
	if(m == n)
	{
		for(int i = 1; i <= n; ++i)
		{
			if(a[i] == 'Y')
			{
				printf("NO");
				return 0;
			}
		}
		printf("YES");
		return 0;
	}

	int cnt = 0, ansn = 0;
	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'N')
		{
			cnt++;
		}
		else
		{
			cnt = 0;
		}

		ansn = max(ansn, cnt);
	}

	if(ansn > m)
	{
		printf("NO");
		return 0;
	}
	if(ansn == m)
	{
		printf("YES");
		return 0;
	}

	//针对？的情况
	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'Y')
			continue;
		if(i + m > n + 1)
			break;

		bool ok = true; //一开始认为是好的
		for(int k = i; k <= i + m - 1; ++k)
		{
			if(a[k] == 'Y') //判断是否是好的
			{
				ok = false;
				break;
			}
		}
		if(ok && a[i + m] != 'N')
		{
			printf("YES");
			return 0;
		}
	 }
	 printf("NO");

	return 0;
}

//#include <bits/stdc++.h>
#include <iostream>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <vector>
#include <deque>
#include <stack>
#include <fstream>
#include <cmath>
#include <cassert>
using namespace std;

#define MOD 1000000007

vector<uint64_t> factors(uint64_t x) {
    set<uint64_t> fac;
    vector<uint64_t> space;
    for (uint64_t i = 1; i <= uint64_t(sqrt(x)); i++) {
        if (x % i == 0) {
            fac.insert(x / i);
            fac.insert(i);
        }
    }

    for (auto& y : fac) {
        space.push_back(y);
    }
    return space;
}

int main() {
	std::ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);

	uint64_t n, k;
	cin >> n>> k;
    string s;
    cin >> s;
    int maxi = 0;
    int curr = 0;
    for (int i = 0; i < s.size(); i++) {
        if (s[i] == 'N') {
            curr++;
        }
        else {
            maxi = max(maxi, curr);
            curr = 0;
        }
    }
    maxi = max(maxi, curr);
    if (curr > k) {
        cout << "NO" << endl;
        return 0;
    }
    else {
        if (curr == k) {
            cout << "YES" << endl;
            return 0;
        }
        else {
            for (int i = 0; i <= s.size()-k; i++) {
                bool valid = true;
                if (i > 0 && s[i - 1] == 'N') continue;
                for (int j = 0; j < k; j++) {
                    if (s[i + j] == 'Y') {
                        valid = false;
                        break;
                    }
                }
                if (valid) {
                    if (i + k < s.size() && s[i + k] != 'N') {
                        cout << "YES" << endl;
                        return 0;
                    }
                }
            }
            cout << "NO" << endl;
            return 0;
        }
    }

	return 0;
}

#include <bits/stdc++.h>

using namespace std;

string s;

int main() {
 int n, k;
 cin >> n >> k >> s;
 s = "Y" + s + "Y";
int j = 0; int d = 0; int mn = 0; int ok = 0;
 for(int i = 1; i <= n+1; i++) {
  if(s[i] != 'N') {
   if(i-j-1 >= k) ok = 1;
   d = 0;
   if(s[i] == 'Y') j = i;
  }
  else mn = max(mn, ++d);
 }
 if(ok && mn <= k) cout << "YES" << endl;
 else cout << "NO" << endl;
}

#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <vector>

#define ll long long
#define pb push_back
using namespace std;

int main() {
	int n,k;
	scanf("%d%d", &n, &k);
	char s[105];
	scanf("%s", &s);
	s[n] = 'Y';
	int t,mx = 0;
	for (int i=0;i<n;++i)
	{
		t = 0;
		while(i<n && s[i]=='N')
		{
			t++;
			i++;
		}
		if (t>k)
		{
			cout<<"NO";
			return 0;
		}
		if (t>mx)
			mx = t;
		if (t!=0)
			i--;
	}
	if (mx==k)
	{
		cout<<"YES";
		return 0;
	}

//	cout<<mx<<endl;

	int j = -1;
	for (int i=0;i<n;++i)
	{
		cout<<i<<endl;
		t = 0;
		while(s[i]=='?' || s[i]=='N')
		{
			if (s[i]=='?' && j==-1)
				j = i;
			t++;
			i++;
			if (t==k)
			{
				if (s[i]=='N')
					break;
				else
				{
					cout<<"YES";
					return 0;
				}
			}
		}
		if (j!=-1)
		{
			i = j;
			j = -1;
		}
	}
cout<<"NO";
return 0;
}

#include <algorithm>
#include <vector>
#include <iostream>
#include <map>
#include <fstream>
#include <set>
#include <queue>
#include <cmath>
#define all(x) x.begin(), x.end()

using namespace std;
typedef long long ll;

int main() {
	cin.tie(0), cout.tie(0), ios_base::sync_with_stdio(0);
	string s;
	int n, k;
	cin >> n >> k >> s;
	s = s + '8';
	vector<int>pr(s.size() + 1, 0), pp(s.size() + 1, 0);
	for (int i = s.size() - 1; i >= 0; --i) {
		if (s[i] == 'N')pp[i] = pp[i + 1] + 1;
		if (s[i] != 'Y')pr[i] = pr[i + 1] + 1;
	}
	bool ok = 0;
	for (int i = 0; i < s.size(); ++i) {
		if (pr[i] >= k && s[i + k] != 'N') {
			if (i > 0 && s[i - 1] != 'N' || i == 0) {
				ok = 1;
				//cout << i << " " << pr[i]<<"\n";
			}
		}
	}
	for (int i = 0; i < s.size() - 1; i++) {
		if (pp[i] > k) {
			cout << "NO"; exit(0);
		}
	}
	if (ok)cout << "YES";
	else cout << "NO";
	return 0;
}/*
 0 7
 N??NN??NY

 */

#include <stdio.h>
#include <bits/stdc++.h>

#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)

#define file ""

using namespace std;
using ll = long long;
using ull = unsigned long long;
using str = string;
using srt = short;

const int INF = (int)1e9 + 7;
const int mod = 998244353;
const ll inf = (ll)1e18;
const ull oo = 1000000000000001;
const int N = 200005;

signed main()
{
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	ios::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr); //freopen(file".in", "r", stdin); freopen(file".out", "w", stdout);

	int n, k;
	cin >> n >> k;
	str s;
	cin >> s;
	s = '#' + s + '#';
	int cnt = 0;
	for (int i = 1; i <= n; ++i)
	{
		if (s[i] == 'N')
			++cnt;
		else
			cnt = 0;
	}
	if (k < cnt || n < k)
	{
		cout << "NO";
	}
	else
	{
		for (int i = 1; i + k - 1 <= n; ++i)
		{
			bool ok = (s[i - 1] != 'N' && s[i + k] != 'N');
			for (int j = i; ok && j <= i + k - 1; ++j)
			{
				ok &= (s[j] != 'Y');
			}
			if (ok)
			{
				cout << "YES";
				return 0;
			}
		}
		cout << "NO";
	}
}

#include <bits/stdc++.h>
using namespace std;
int main() {
    int n,k; string s; cin>>n>>k>>s; bool flag = false;
    for(int i = k; i <= n; ++i) {
        string t = s;
        for(int j = 1; j <= i-k; ++j)
            if(t[j-1] == '?') t[j-1] = 'Y';
        for(int j = i; j <= n; ++j)
            if(t[j-1] == '?') t[j-1] = 'Y';
        for(int j = i-k+1; j <= i; ++j)
            if(t[j-1] == '?') t[j-1] = 'N';
        int c = 0, m = 0;
        for(int i = 1; i <= n; ++i) {
            if(t[i-1] == 'N') ++c;
            else {
                m = max(m,c);
                c = 0;
            }
        }
        if(m == k) {
            flag = true;
            break;
        }
    }
    if(flag) cout<<"YES\n";
    else cout<<"NO\n";
}

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

	typedef tree<
			int,
			null_type,
			less<int>,
			rb_tree_tag,
			tree_order_statistics_node_update>
	ordered_set;

#define ll long long

int main(){
	ios::sync_with_stdio(false);cin.tie(0);
	ll n,k;cin>>n>>k;
	string str;cin>>str;
	ll max_val=0;
	if(str[0]=='N') max_val++;
	ll temp=max_val;
	for(int i=1;i<str.length();i++){
		if(str[i]=='N' || str[i]=='?'){
			temp++;
			max_val=max(max_val,temp);
		}else{
			temp=0;
			while(i<str.length() && (str[i]!='N' &&  str[i]=='?')){
				i++;
			}
			if(i<str.length() && ( str[i]=='N' || str[i]=='?') ){
				temp=1;
				max_val=max(max_val,temp);
			}
		}
	}
	if(max_val>=k) cout<<"YES\n";
	else cout<<"NO\n";
	return 0;

}

#include <bits/stdc++.h>
#define maxn 110
using namespace std;

char a[maxn];
int f[maxn], g[maxn];
int n, m;
int ans;

int main()
{
	scanf("%d%d", &n, &m);
	gets(a + 1);
	gets(a + 1);

	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'N' && a[i - 1] != 'N')
		{
			f[i] = 1;
		}
	}
	/*
	for(int i = 1; i <= n; ++i)
		printf("%d ", f[i]);
	cout << endl;
	*/

	bool flag = false;
	for(int i = 1; i <= n; ++i)
	{
		if(a[i - 1] == a[i] && a[i] == 'N')
		{
			f[i] = f[i - 1] + 1;
		}
		if(f[i] == m && a[i + 1] != 'N')
		{
			flag = true;
		}
	}
	if(flag)
	{
		for(int i = 1; i <= n; ++i)
		{
			if(f[i] > m)
			{
				printf("NO\n");
				return 0;
			}
		}
		printf("YES\n");
		return 0;
	}

	//考虑有?的情况
	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'Y')
			continue;
		int tem = (f[i] != 0) ? f[i] : 0;
		if(a[i] == '?')
		{
			tem++;
		}
		if(a[i - 1] == '?')
		{
			int x = i - 1;
			while(a[x] == '?' || a[x] == 'N')
			{
				tem++;
				if(tem == m && a[x - 1] != 'N')
				{
					printf("Yes\n");
					return 0;
				}

				x--;
			}
		 }
		 if(a[i + 1] == '?')
		 {
		 	int y = i + 1;
		 	while(a[y] == '?' || a[y] == 'N')
		 	{
		 		tem++;
		 		if(tem == m && a[y + 1] != 'N')
		 		{
		 			printf("YES\n");
		 			return 0;
				 }

				 y++;
			 }
		 }
	}

	printf("NO\n");

	return 0;
}

#include <bits/stdc++.h>
#define maxn 106
using namespace std;

char a[maxn];
int f[maxn], g[maxn];
int n, m;
int ans;

int main()
{
	scanf("%d%d", &n, &m);
	gets(a + 1);
	gets(a + 1);

	bool flag = true;
	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'N' && a[i - 1] != 'N')
		{
			f[i] = 1;
		}
	}

	for(int i = 2; i <= n; ++i)
	{
		if(a[i - 1] == a[i] && a[i] == 'N')
		{
			f[i] = f[i - 1] + 1;
		}
		if(f[i] > m)
		{
			printf("NO\n");
			return 0;
		}
		if(f[i] == 2)
		{
			printf("YES\n");
			return 0;
		}
	}

	//考虑有?的情况
	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'Y')
			continue;
		int tem = (f[i] != 0) ? f[i] : 0;
		if(a[i] == '?')
		{
			tem++;
		}
		if(a[i - 1] == '?')
		{
			int x = i - 1, ans = tem;
			while(a[x] == '?')
			{
				tem++;
				if(tem == m && a[x - 1] != 'N')
				{
					printf("Yes\n");
					return 0;
				}

				x--;
				while(a[x] == 'N')
				{
					tem ++;
					x--;
					if(tem == m && a[x] != 'N')
		 			{
		 				printf("YES\n");
		 				return 0;
				 	}
				}
			}
		 }
		 if(a[i + 1] == '?')
		 {
		 	int y = i + 1;
		 	while(a[y] == '?')
		 	{
		 		tem++;
		 		if(tem == m && a[y + 1] != 'N')
		 		{
		 			printf("YES\n");
		 			return 0;
				 }

				 y++;
				 while(a[y] == 'N')
				 {
				 	tem++;
				 	y++;
				 	if(tem == m && a[y] != 'N')
		 			{
		 				printf("YES\n");
		 				return 0;
				 	}
				 }
			 }
		 }
	}

	printf("NO\n");

	return 0;
}

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

int main(){

    //Stepan's Series

    int i, n, k, prev, now, ans;
    string s;

    cin>>n>>k;
    cin>>s;

    prev=0;
    ans=0;

    for (i=0;i<n;i++){
        if (s[i]=='N'){
            now=prev+1;
        }
        else {
            now=0;
        }
        prev=now;
        ans=max(ans, now);
    }

    if (ans==k){
        cout<<"YES\n";
    }
    else if (ans<k){
        int j;
        bool b=true;
        vector <int> v;
        for (i=0;i<n;i++){
            if (s[i]=='N'||s[i]=='?'){
                if (b){
                    v.push_back(i);
                    b=false;
                }
            }
            else {
                b=true;
            }
        }
        for (i=0;i<v.size();i++){
            prev=0;
            ans=0;
            for (j=v[i];j<n;j++){
                if (s[j]=='N'){
                    now=prev+1;
                }
                else if (s[j]=='?'){
                    if (ans<k){
                        now=prev+1;
                    }
                    else {
                        now=0;
                    }
                }
                else {
                    now=0;
                }
                prev=now;
                ans=max(ans, now);
            }
            if (ans==k){
                break;
            }
        }
        if (ans==k){
            cout<<"YES\n";
        }
        else {
            cout<<"NO\n";
        }
    }
    else {
        cout<<"NO\n";
    }

    return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <ctime>
#include <cmath>
#include <string>
#include <stdlib.h>
#include <fstream>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <deque>
#include <iterator>
#include <iomanip>
#include <climits>
#include <numeric>
#include <cstring>
#include <list>
using namespace std;
#define ll long long int

const int MAXN = 2e5 + 1;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n, k;
    string s;
    cin >> n >> k >> s;

    int cnt = 0, a = 0;

    for(int i = 0; i < n; ++i){
        if(s[i] == 'N'){
            if(i && s[i - 1] == 'N') cnt++;
            else cnt = 1;
        }
        if(s[i] != 'N') cnt = 0;

        a = max(a, cnt);
    }

    if(a > k){
        cout << "NO\n";
        return 0;
    }

    for(int i = 0; i < n - k; ++i){
        bool ok = true;
        if(i && s[i - 1] == 'N') continue;
        if(i + k != n - 1 && s[i + k + 1] == 'N') continue;
        for(int j = i; j < i + k; ++j){
            if(s[j] == 'Y'){
                ok = false;
                break;
            }
        }

        if(ok){
            cout << "YES\n";
            return 0;
        }
    }

    cout << "NO\n";
}

#include<bits/stdc++.h>
using namespace std;

#define ll       long long int
#define ull      unsigned long long int
#define pb       push_back
#define vpop     pop_back
#define mp       make_pair
#define ff       first
#define ss       second
#define clz(x)   __builtin_clz(x)       //count leading zeroes
#define ctz(x)   __builtin_ctz(x)       //count trailing zeroes
#define sbts(x)  __builtin_popcount(x) //count set bits
#define ps(x, y) fixed << setprecision(y) << x
#define all(v)   v.begin(), v.end()
#define umap	 unordered_map
const int MOD  =  1e9 + 7;
const ll INF   =  1e12;
int n, k;
int memo[101][101][101];

int solve(string &str, int i, int N, int _max) {
    _max = max(N, _max);
    int &a = memo[i][N][_max];
    if(a != -1) return a;
    if(i == n)  return a = ((_max == k)? 1: 0);
    bool temp1 = solve(str, i+1, 0, _max);
    if(str[i] == 'Y' || temp1)   return a = temp1;
    return a = solve(str, i+1, N+1, _max);
}

int main() {
    ios_base::sync_with_stdio(false);   cin.tie(NULL);
    memset(memo, -1, sizeof(memo));
    cin >> n >> k;
    string str; cin >> str;
    cout << (solve(str, 0, 0, 0)? "YES": "NO");
    return 0;
}

#include <iostream>
#include <string>

using namespace std;

int main()
{
	int n, k;
	cin >> n >> k;

	string s;
	cin >> s;

	int cnt = 0;

	for (int i = 0; i < n; i++) {
		cnt = (s[i] == 'N') ? cnt + 1 : 0;
		if (cnt > k) {
			cout << "NO";
			return 0;
		}
	}

	for (int i = 0; i < n - k; i++) {
		bool is_cont_y = false;
		for (int j = 0; !is_cont_y && j < k; j++)
			is_cont_y = s[i + j] == 'Y';

		if (!is_cont_y) {
			cout << "YES";
			return 0;
		}
	}

	cout << "NO";
}

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <cstring>
#include <string>
#include <vector>
#define MIN 1<<31-1
#define REP(i,n) for(int i = 0; i < (n); i++)
typedef long long int ll;
char NN[10000];
int zu[10000];
using namespace std;
int main()
{
	int n,k,l,r;
	cin>>n>>k;
	l=0;r=0;
	int flag=0;
	int nowl=0;
	int cou=0;
	for(int i=0;i<n;i++)
	{
		cin>>NN[i];
	}
	int i;
	for(i=0;i<n;i++)
	{
		if((NN[i]=='N'||NN[i]=='?')&&NN[i-1]!='N')
		{
			int w;
			for(w=1;w<k;w++)
				if(w+i>=n||NN[w+i]=='Y')
					break;
			if(w==k&&NN[i+w]!='N'||k==0)
			{
				break;
			}
		}
	}
	int out=0;
	if(i!=n)
		out=1;
	int mi=0;
	int nmi=0;
	for(i=0;i<n;i++)
	{
		if(NN[i]=='N')
		{
			nmi++;
		}
		else
		{
			mi=max(mi,nmi);
			nmi=0;
		}
	}
	mi=max(mi,nmi);
	if(out==1&&mi<=k)
		cout<<"YES";
	else
		cout<<"NO";
	return 0;
}

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <cstring>
#include <string>
#include <vector>
#define MIN 1<<31-1
#define REP(i,n) for(int i = 0; i < (n); i++)
typedef long long int ll;
char NN[10000];
int zu[10000];
using namespace std;
int main()
{
	int n,k,l,r;
	cin>>n>>k;
	l=0;r=0;
	int flag=0;
	int nowl=0;
	int cou=0;
	for(int i=0;i<n;i++)
	{
		cin>>NN[i];
	}
	int i;
	for(i=0;i<n;i++)
	{
		if((NN[i]=='N'||NN[i]=='?')&&NN[i-1]!='N')
		{
			int w;
			for(w=1;w<k;w++)
				if(w+i>=n||NN[w+i]=='Y')
					break;
			if(w==k&&NN[i+w+1]!='N')
			{
				break;
			}
		}
	}
	int out=0;
	if(i!=n)
		out=1;
	int mi=0;
	int nmi=0;
	for(i=0;i<n;i++)
	{
		if(NN[i]=='N')
		{
			nmi++;
		}
		else
		{
			mi=max(mi,nmi);
			nmi=0;
		}
	}
	mi=max(mi,nmi);
	if(out==1&&mi<=k)
		cout<<"YES";
	else
		cout<<"NO";
	return 0;
}

#include <bits/stdc++.h>
using namespace std;

const int N = 105;

char s[N];

bool dp[N][N][2];

bool solveDp(int ind,int cons,int g,int n,int k) {
    if(cons>k) {
        return false;
    }
    if(ind==n) {
        if(g) {
            return true;
        }
        else {
            return false;
        }
    }
    if(dp[ind][cons][g]) {
        return false;
    }
    dp[ind][cons][g] = true;
    if(s[ind]=='?') {
        int tmp = 0;
        int ng = g;
        if(tmp==k) {
            ng = 1;
        }
        if(solveDp(ind+1,tmp,ng,n,k) ){
            return true;
        }
        tmp = cons+1;
        ng = g;
        if(tmp==k) {
            ng = 1;
        }
        if(solveDp(ind+1,tmp,ng,n,k) ){
            return true;
        }
    }
    else if(s[ind]=='Y') {
        int tmp = 0;
        int ng = g;
        if(solveDp(ind+1,tmp,ng,n,k) ) {
            return true;
        }
    } else {
        int tmp = cons+1;
        int ng = g;
        if(tmp==k) {
            ng = 1;
        }
        if(solveDp(ind+1,tmp,ng,n,k) ) {
            return true;
        }
    }
    return false;
}

void solve() {
    int n,k;
    scanf("%d %d",&n,&k);
    scanf("%s",s);
    int g = 0;
    return;
    if(k==0) {
        g = 1;
    }
    if(solveDp(0,0,g,n,k)) {
        cout<<"YES\n";
    } else {
        cout<<"NO\n";
    }
}

int main()
{
    solve();
}

#include <bits/stdc++.h>
using namespace std;
int main() {
    int n,k; string s; cin>>n>>k>>s; bool flag = false;
    for(int i = k; i <= n; ++i) {
        string t = s;
        for(int j = 1; j <= i-k; ++j)
            if(t[j-1] == '?') t[j-1] = 'Y';
        for(int j = i; j <= n; ++j)
            if(t[j-1] == '?') t[j-1] = 'Y';
        for(int j = i-k+1; j <= i; ++j)
            if(t[j-1] == '?') t[j-1] = 'N';
        int c = 0, m = 0;
        for(int i = 1; i <= n; ++i) {
            if(t[i-1] == 'N') ++c;
            else {
                m = max(m,c);
                c = 0;
            }
        }
        m = max(m,c);
        if(m == k) {
            flag = true;
            break;
        }
    }
    if(flag) cout<<"YES\n";
    else cout<<"NO\n";
}

//
//  main.cpp
//  test
//
//  Created by Максим Бачурин on 04.02.17.
//  Copyright © 2017 Максим Бачурин. All rights reserved.
//

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <utility>
#include <set>
#include <map>
#include <list>
#include <queue>
#include <algorithm>
#include <iomanip>
using namespace std;
#define all(x) (x).begin(),(x).end()
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> PII;
const ll mod = 1e9 + 7;
//const double eps = 1e-9;
const int inf = 1e9;
//const double PI = 3.1415926535897932384626433832795;
const int N = 40005;

int main()
{
    //freopen("output.txt", "r", stdin);
    //freopen("output2.txt", "w", stdout);
    ios_base::sync_with_stdio(0);
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    int t1 = 0, t2 = 0, maxn = 0, maxnv = 0;
    for(int i = 0; i < s.size(); i++)
    {
        if(s[i] == 'N')
        {
            t1++;
            t2++;
            maxn = max(maxn, t1);
            maxnv = max(maxnv, t2);
        }
        if(s[i] == '?')
        {
            //cout << t1 << endl;
            t1 = 0;
            t2++;
            maxnv = max(maxnv, t2);
            if(s[i+1]!='?')
            {
                t2 = 0;
            }
        }
        if(s[i] == 'Y')
        {
            //cout << t1 << endl;
            t1 = 0;
            t2 = 0;
        }
    }
    maxn = max(maxn, t1);
    maxnv = max(maxnv, t2);
    if(maxn <= k && k <= maxnv)
    {
        cout << "YES";
    }
    else
        cout << "NO";
    cout << endl;
    return 0;
}

#include <iostream>
#include <fstream>
#include <cstdio>
#include <queue>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <stack>
#include <cstring>
#include <cmath>

#define MN 1000010
#define INF 2147483647
#define PI 3.14159265359
#define pairr pair<int, int>
#define pairrr pair<int, pairr>
#define f first
#define s second
#define pb push_back
#define ll long long
#define MOD 10000007
#define IO ios_base::sync_with_stdio(false); cin.tie();
#define PQT pairr
#define PQL priority_queue<PQT, vector<PQT>, less<PQT> >
#define PQG priority_queue<PQT, vector<PQT>, greater<PQT> >

using namespace std;

int n,k,i,t,z,ans=-1;
string s;

int main()
{
    IO
//    freopen("input.txt","r",stdin);
//    freopen("output.txt","w",stdout);
    cin>>n>>k;
    cin>>s;
    for (i=0;i<s.length();i++)
    {
        if (s[i]=='Y')
        {
            if (t==k)
            {
                ans=1;
                break;
            }
            if (t>k)
            {
                ans=0;
                break;
            }
            t=0;
        }
        else
        if (s[i]=='N')
        {
            t++;
        }
    }
            if (t==k)
            {
                ans=1;
            }
            if (t>k) ans=0;
    if (ans==1) cout<<"YES\n";
    else
    if (ans==0) cout<<"NO\n";
    else
    {
        t=0;
        for (i=0;i<s.length();i++)
        {
            if (s[i]=='Y')
            {
                if (t+z>=k)
                {
                    ans=1;
                    break;
                }
                t=0;
                z=0;
            }
            else
            if (s[i]=='?')
            {
                z++;
            }
            else
            {
                t++;
            }
        }
        if (ans) cout<<"YES\n";
        else cout<<"NO\n";
    }
    return 0;
}

#include <iostream>
#include <algorithm>
#include <string>

using namespace std;

int main() {
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    int mx = 0, cur = 0;
    for (int i = 0; i < n; ++i) {
        if (s[i] != 'N') {
            mx = max(mx, cur);
            cur = 0;
        } else {
            ++cur;
        }
    }
    mx = max(mx, cur);
    if (mx > k) {
        cout << "NO\n";
        return 0;
    }
    int Y = 0;
    for (int i = 0; i < k; ++i) {
        Y += (s[i] == 'Y');
    }
    if (Y == 0) {
        cout << "YES\n";
        return 0;
    }
    for (int r = k; r < n; ++r) {
        if (s[r - k] == 'Y') {
            --Y;
        }
        if (s[r] == 'Y') {
            ++Y;
        }
        if (Y == 0) {
            cout << "YES\n";
            return 0;
        }
    }
    cout << "NO\n";
    return 0;
}

#include <iostream>
#include <stdio.h>
#include <cmath>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <deque>
#include <stack>
#include <string>
#include <bitset>
using namespace std;

#define in(s) freopen(s, "r", stdin);
#define out(s) freopen(s, "w", stdout);
#define forn(i, n) for (int i = 0; i < n; i++)
#define endl '\n'

typedef long long ll;
typedef long double ld;

int main()
{
	//in("cakes.in");
	//out("cakes.out");
	srand(1373737);
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int n, k;
	cin >> n >> k;

	string s;
	cin >> s;

	int p = 0, len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			p++;
		}
		len = max(len, now);
		if (now == k)
		{
			cout << "YES";
			return 0;
		}
	}
	if (len > k)
	{
		cout << "NO";
		return 0;
	}
	vector <bool> fix(n);
	forn(i, n)
	{
		if (s[i] == '?')
			s[i] = 'N';
		else
			fix[i] = true;
	}
	p = 0; len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0, start = p;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			p++;
			if (now == k)
			{
				if ((start - 1 < 0 || !fix[start - 1]) && (p + 1 >= n || !fix[p + 1]))
				{
					cout << "YES";
					return 0;
				}
				else
				{
					now--;
					start++;
				}
			}
		}
	}
	cout << "NO";
	return 0;
}

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
#define inf 0x3f3f3f3f
char a[250];
int main()
{
   int n,k;
   scanf("%d%d",&n,&k);
   getchar();
   for(int i=0;i<n;i++)
   {
       scanf("%c",&a[i]);
       a[i+n]=a[i];
   }
  // printf("%s",a);
   int p=1,kk,maxx=0;
   for(int i=0;i<2*n;i+=p)
   {
       if(a[i]=='N')
       {
           kk=0;
           for(int j=i;j<2*n;j++)
           {
               if(a[j]=='N')
               {
                    kk++;
               }
                else
                {
                    p=j-i;
                    break;
                }
           }
          // printf("%d\n",i);
           maxx=max(maxx,kk);
       }
   }
   if(maxx>k)
   printf("NO\n");
   else printf("YES\n");
}

#include <iostream>

using namespace std;

int main() {
    int n, k;
    cin >> n >> k;
    char c;
    int cnt1 = 0, cnt2 = 0;
    int cur1 = 0, cur2 = 0;
    for (int i = 0; i < n; i++){
        cin >> c;
        if (c == '?') {
            cur1++;
            cur2 = 0;
        }
        else if (c == 'N') {
            cur2++;
            cur1++;
        }
        else if (c == 'Y') {
            cur2 = 0;
            cur1 = 0;
        }
        cnt1 = max(cnt1, cur1);
        cnt2 = max(cnt2, cur2);
    }
    //cout << cnt1 << ' ' << cnt2 << '\n';
    if (cnt1 >= k && cnt2 <= k) {
        cout << "YES\n";
    } else {
        cout << "NO\n";
    }
}

#include <algorithm>
#include <vector>
#include <iostream>
#include <map>
#include <fstream>
#include <set>
#include <queue>
#include <cmath>
#define all(x) x.begin(), x.end()

using namespace std;
typedef long long ll;

int main() {
	cin.tie(0), cout.tie(0), ios_base::sync_with_stdio(0);
	string s;
	int n, k;
	cin >> n >> k >> s;
	s = s + '8';
	vector<int>pr(s.size() + 1, 0), pp(s.size() + 1, 0);
	for (int i = s.size() - 1; i >= 0; --i) {
		if (s[i] == 'N')pp[i] = pp[i + 1] + 1;
		if (s[i] != 'Y')pr[i] = pr[i + 1] + 1;
	}
	bool ok = 0;
	for (int i = 0; i < s.size(); ++i) {
		if (pr[i] >= k && s[i + k] != 'N') {
			if (i > 0 && s[i - 1] != 'N' || i == 0) {
				ok = 1;
				//cout << i << " " << pr[i]<<"\n";
			}
		}
	}
	for (int i = 0; i < s.size() - 1; i++) {
		if (pp[i] > k) {
			cout << "NO"; exit(0);
		}
	}
	if (ok)cout << "YES";
	else cout << "NO";
	return 0;
}/*
 0 7
 N??NN??NY

 */

#include <bits/stdc++.h>
#define maxn 110
using namespace std;

char a[maxn];
int f[maxn], g[maxn];
int n, m;
int ans;

int main()
{
	scanf("%d%d", &n, &m);
	gets(a + 1);
	gets(a + 1);

	if(m == 0)
	{
		for(int i = 1; i <= n; ++i)
		{
			if(a[i] == 'N')
			{
				printf("NO\n");
				return 0;
			}
		}
		//printf("YES\n");
		//return 0;
	}

	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'N' && a[i - 1] != 'N')
		{
			f[i] = 1;
		}
	}
	/*
	for(int i = 1; i <= n; ++i)
		printf("%d ", f[i]);
	cout << endl;
	*/

	bool flag = false;
	for(int i = 1; i <= n; ++i)
	{
		if(a[i - 1] == a[i] && a[i] == 'N')
		{
			f[i] = f[i - 1] + 1;
		}
		if(f[i] == m && a[i + 1] != 'N')
		{
			flag = true;
		}
	}
	if(flag)
	{
		for(int i = 1; i <= n; ++i)
		{
			if(f[i] > m)
			{
				printf("NO\n");
				return 0;
			}
		}
		printf("YES\n");
		return 0;
	}

	//考虑有?的情况
	for(int i = 1; i <= n; ++i)
	{
		if(a[i] == 'Y')
			continue;
		int tem = (f[i] != 0) ? f[i] : 0;
		if(a[i] == '?')
		{
			tem++;
			if(tem == m && a[i + 1] != 'N')
			{
				printf("YES\n");
				return 0;
			}
		}
		if(a[i - 1] == '?')
		{
			int x = i - 1;
			while(a[x] == '?' || a[x] == 'N')
			{
				tem++;
				if(tem == m && a[x - 1] != 'N')
				{
					printf("Yes\n");
					return 0;
				}

				x--;
			}
		 }
		 if(a[i + 1] == '?')
		 {
		 	int y = i + 1;
		 	while(a[y] == '?' || a[y] == 'N')
		 	{
		 		tem++;
		 		if(tem == m && a[y + 1] != 'N')
		 		{
		 			printf("YES\n");
		 			return 0;
				 }

				 y++;
			 }
		 }
	}

	printf("NO\n");

	return 0;
}

#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <vector>
#include <set>
#include <string>
#include <map>
#include <algorithm>
#include <memory.h>

using namespace std;
long long MOD = 1000000007;
string go;
int sost[101][101];
int k;
int din (int pos, int least)
{
	if (sost[pos][least] != -1)
		return sost[pos][least];
	int ma = -1e9;
	if (pos == 0)
	{
		if (least == 1 && (go[0] == 'N' || go[0] == '?'))
			return 1;

		if (least == 0 && go[0] == 'N')
			return -1e9;

		return 0;
	}
	if (go[pos] == 'N' && least == 0)
		return -1e9;

	if (least == 0 && (go[pos] == '?' || go[pos] == 'Y'))
		ma = max(ma, din(pos - 1, k))+1;

	if (least != 0 && go[pos] == '?')
	{
		ma = max(ma, din(pos - 1, least - 1));
		ma = max(ma, din(pos - 1, k));
	}
	if (least != 0 && go[pos] == 'N')
	{
		ma = max(ma, din(pos - 1, least - 1));
	}
	if (go[pos] == 'Y')
	{
		ma = max(ma, din(pos - 1, k));
	}
	sost[pos][least] = ma;
	return ma;
}
int main()
{
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#else
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
#endif
	int n;
	memset(sost, -1, sizeof(sost));
	cin >> n >> k;
	cin >> go;
	if (din(n - 1, k) > 0)
		puts("YES");
	else
		puts("NO");
	return 0;
}

#include<bits/stdc++.h>

using namespace std;

int main(){

    int n,k;
    cin >> n >> k;

    string s;
    cin >> s;

    int sum[n+10] = {0};
    for(int i = 0;i<n;i++)sum[i+1] = sum[i] + (s[i] == 'N');

    int avl = 0;
    for(int i = 0;i<=(n-k-1);i++){
        int en = i+k+1,st = i;
        if((sum[en]-sum[st]) == (k+1)){
            avl = 1;
            break;
        }
    }

    if(avl == 1){
        cout << "NO" << endl;
        return 0;
    }
    for(int i = 0;i<n;i++)if(s[i] == '?')s[i] = 'N';
    sum[0] = 0;
    for(int i = 0;i<n;i++)sum[i+1]=sum[i] +( s[i]=='N');

    avl = 0;

    for(int i = 0;(i)<=(n-k);i++){
        int en = i + k,st = i;
        if((sum[en]-sum[i]) == k){avl = 1;break;}
    }
    if(avl == 1){
        cout << "YES" << endl;
    }
    else {
        cout << "NO" << endl;
    }

    return 0;
}

#include <bits/stdc++.h>

using namespace std;

string s;

int main() {
 int n, k;
 cin >> n >> k >> s;
 s = "Y" + s + "Y";
queue<int> q; q.push(0); int d = 0; int mn = 0; int ok = 0;
 for(int i = 1; i <= n+1; i++) {
  while(q.size() && i - q.size() - 1 > k) q.pop();

  if(s[i] != 'N') {
   if(q.size() && i - q.size() - 1 == k) ok = 1;
   d = 0;
   q.push(i);
  }
  else mn = max(mn, ++d);
 }
 if(ok && mn <= k) cout << "YES" << endl;
 else cout << "NO" << endl;
}

#include <iostream>
#include <stdio.h>
#include <cmath>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <deque>
#include <stack>
#include <string>
#include <bitset>
using namespace std;

#define in(s) freopen(s, "r", stdin);
#define out(s) freopen(s, "w", stdout);
#define forn(i, n) for (int i = 0; i < n; i++)
#define endl '\n'

typedef long long ll;
typedef long double ld;

int main()
{
	//in("cakes.in");
	//out("cakes.out");
	srand(1373737);
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int n, k;
	cin >> n >> k;

	string s;
	cin >> s;

	int p = 0, len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			p++;
		}
		len = max(len, now);
	}
	if (len > k)
	{
		cout << "NO";
		return 0;
	}
	forn(i, n)
	{
		if (s[i] == '?')
			s[i] = 'N';
	}
	p = 0; len = 0;
	while (p < s.size())
	{
		if (s[p] != 'N')
		{
			p++;
			continue;
		}
		int now = 0;
		while (p < s.size() && s[p] == 'N')
		{
			now++;
			p++;
		}
		len = max(len, now);
	}
	if (len >= k)
	{
		cout << "YES";
	}
	else
	{
		cout << "NO";
	}
	return 0;
}

#include <stdio.h>
#include <bits/stdc++.h>

#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)

#define file ""

using namespace std;
using ll = long long;
using ull = unsigned long long;
using str = string;
using srt = short;

const int INF = (int)1e9 + 7;
const int mod = 998244353;
const ll inf = (ll)1e18;
const ull oo = 1000000000000001;
const int N = 200005;

signed main()
{
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	ios::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr); //freopen(file".in", "r", stdin); freopen(file".out", "w", stdout);

	int n, k;
	cin >> n >> k;
	str s;
	cin >> s;
	s = '#' + s + '#';
	int cnt = 0;
	for (int i = 1; i <= n; ++i)
	{
		if (s[i] == 'N')
			++cnt;
		else
			cnt = 0;
	}
	if (k < cnt || n < k)
	{
		cout << "NO";
	}
	else
	{
		for (int i = 1; i + k - 1 <= n; ++i)
		{
			bool ok = (s[i - 1] != 'N' && s[i + k] != 'N');
			for (int j = i; ok && j <= i + k - 1; ++j)
			{
				ok &= (s[j] != 'Y');
			}
			if (ok)
			{
				cout << "YES";
				return 0;
			}
		}
		cout << "NO";
	}
}

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define PI 3.1415926535
using namespace __gnu_pbds;
using namespace std;

typedef long long ll;
typedef pair <ll, ll> pll;

bool check(string &s, ll k) {
    ll cnt = 0;
    for(auto i: s) {
        if(i == 'N') cnt++;
        else cnt = 0;
        if(cnt > k) return false;
    }
    return true;
}

int main(){
    ios_base:: sync_with_stdio(0);
    //start();
    ll n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    if(!check(s, k)) {
        cout << "NO";
        return 0;
    }
    for(ll i = 0; i < n; i++) {
        if(s[i] == '?' || s[i] == 'N') {
            ll cnt = 0;
            while(i + cnt < n && ((s[i + cnt] == '?' && cnt < k) || s[i + cnt] == 'N')) {
                cnt++;
            }
            //cout << cnt << endl;
            if(cnt == k) {
                cout << "YES";
                return 0;
            }
        }
    }
    cout << "NO";
    return 0;
}