High school student Vasya got a string of length n as a birthday present. This string consists of letters 'a' and 'b' only. Vasya denotes beauty of the string as the maximum length of a substring (consecutive subsequence) consisting of equal letters.Vasya can change no more than k characters of the original string. What is the maximum beauty of the string he can achieve?

The first line of the input contains two integers n and k (1 ≤ n ≤ 100 000, 0 ≤ k ≤ n) — the length of the string and the maximum number of characters to change. The second line contains the string, consisting of letters 'a' and 'b' only.

Print the only integer — the maximum beauty of the string Vasya can achieve by changing no more than k characters.

NoteIn the first sample, Vasya can obtain both strings "aaaa" and "bbbb".In the second sample, the optimal answer is obtained with the string "aaaaabaa" or with the string "aabaaaaa".

object Solution extends App {
  val in = io.Source.stdin.getLines()
  val Array(n, k) = in.next().split(' ').map(_.toInt)
  val line = in.next()
  val (at, _, _, bt, _, _) = line.indices.foldLeft((0, 0, k, 0, 0, k)) {
    case (att@(amax, acurrent, aleft, bmax, bcurrent, bleft), i) =>
//      println(att)
      val ch = line(i)
//      println(ch)
      if (ch == 'a') {
        if (bleft > 0)
          (Math.max(amax, acurrent + 1), acurrent + 1, aleft, Math.max(bmax, bcurrent + 1), bcurrent + 1, bleft - 1)
        else {
          var ni = bcurrent
          while (ni > 0 && line(i - ni) != 'a')
            ni -= 1
//          println("ni " + ni)
          if (ni > 0)
            (Math.max(amax, acurrent + 1), acurrent + 1, aleft, Math.max(bmax, ni), ni, bleft)
          else
            (Math.max(amax, acurrent + 1), acurrent + 1, aleft, bmax, 0, k)
        }
      }
      else {
        if (aleft > 0)
          (Math.max(amax, acurrent + 1), acurrent + 1, aleft - 1, Math.max(bmax, bcurrent + 1), bcurrent + 1, bleft)
        else {
//          println("acurrent " + acurrent)
//          println("i = " + i)
          var ni = acurrent
          while (ni > 0 && line(i - ni) != 'b')
            ni -= 1
//          println("NI a " + ni)

          if (ni > 0)
            (Math.max(amax, ni), ni, aleft, Math.max(bmax, bcurrent + 1), bcurrent + 1, bleft)
          else
            (amax, 0, k, Math.max(bmax, bcurrent + 1), bcurrent + 1, bleft)
        }
      }
  }
  println(Math.max(at, bt))
}

object C676 {

  import IO._
  import collection.{mutable => cu}

  def main(args: Array[String]): Unit = {
    val Array(n, k) = readInts(2)
    val str = read
    val charCountA = Array.fill(n+1)(0)
    val charCountB = Array.fill(n+1)(0)
    for(i <- 1 to n) {
      charCountA(i) = charCountA(i-1)
      charCountB(i) = charCountB(i-1)

      if(str(i-1) == 'a')
        charCountA(i) += 1
      else
        charCountB(i) += 1
    }

    var res = 0

    def lastOccuranceOrLowerBinarySearch(arr: Array[Int], i: Int, target: Int): Int = {
      var low = i+1
      var high = n

      while(low < high) {
        val mid = low + (high-low+1)/2

        if(arr(mid) > target) {
          high = mid - 1
        } else {
          low = mid
        }
      }
      low
    }

    for(i <- 0 until n) {
//      println(i, lastOccuranceOrLowerBinarySearch(charCountA, i, charCountA(i) + k), lastOccuranceOrLowerBinarySearch(charCountB, i, charCountB(i) + k))
      val last = math.max(
        lastOccuranceOrLowerBinarySearch(charCountA, i, charCountA(i) + k),
        lastOccuranceOrLowerBinarySearch(charCountB, i, charCountB(i) + k)
      )

      res = math.max(res, last-i)
    }

    out.println(res)

    out.close()
  }

  object IO {
    private val input = new java.io.BufferedReader(new java.io.InputStreamReader(System.in))
    //    private val input = new java.io.BufferedReader(new java.io.InputStreamReader(new java.io.FileInputStream("src/input")))
    val out = new java.io.PrintWriter(System.out)

    @inline def read: String = input.readLine()

    @inline def tokenizeLine = new java.util.StringTokenizer(read)

    def readInt: Int = tokenizeLine.nextToken.toInt

    def readInts(n: Int): Array[Int] = {
      val tl = tokenizeLine
      Array.fill(n)(tl.nextToken.toInt)
    }

    def readLongs(n: Int): Array[Long] = {
      val tl = tokenizeLine
      Array.fill(n)(tl.nextToken.toLong)
    }

    def readBigs(n: Int): Array[BigInt] = {
      val tl = tokenizeLine
      Array.fill(n)(BigInt(tl.nextToken))
    }
  }

}

import Utils._, annotation.tailrec, collection.mutable, util._, control._, math.Ordering.Implicits._

object _676C extends CodeForcesApp {
  override def apply(io: IO) = {
    val (n, k, s) = io[(Int, Int, String)]

    val pas, pbs = Array.ofDim[Int](n + 1)
    s.indices foreach {i =>
      pas(i + 1) = pas(i) + (s(i) == 'a').to[Int]
      pbs(i + 1) = pbs(i) + (s(i) == 'b').to[Int]
    }

    def solve(l: Int, r: Int): Int = if (r <= n) {
      if(pas(r) - pas(l) <= k || pbs(r) - pbs(l) <= k) {
        solve(l, r + 1) max (r - l)
      } else {
        solve(l + 1, r)
      }
    } else {
      0
    }

    io += solve(0, 0)
  }
}
/****************************[Ignore Template Below]****************************************/
trait CodeForcesApp {
  lazy val isOnlineJudge: Boolean = sys.props.get("ONLINE_JUDGE").exists(_.toBoolean)
  def debug(x: Any): Unit = if (!isOnlineJudge) println(x)
  def apply(io: IO): io.type
  def main(args: Array[String]): Unit = this(new IO(System.in, System.out)).close()
}
object Utils {
  import scala.collection.mutable, mutable.{Map => Dict}
  implicit class GenericExtensions[A](val a: A) extends AnyVal {
    def partialMatch[B](f: PartialFunction[A, B]): Option[B] = f lift a
  }
  implicit class TraversableExtensions[A, C[X] <: Traversable[X]](val t: C[A]) extends AnyVal {
    def onlyElement: A = t.head.ensuring(t.size == 1)
    def groupByIdentifier[K](f: A => K): Map[K, A] = t.groupBy(f).mapValues(_.onlyElement)
    def duplicates(implicit b: C of A): C[A] = {
      val elems = mutable.Set.empty[A]
      (t collect {case i if !elems.add(i) => i}).to[C]
    }
    def sumWith[B](f: A => B)(implicit n: Numeric[B]): B = t.foldLeft(n.zero) {case (p, i) => n.plus(p, f(i))}
    def zipWith[B](f: A => B)(implicit b: C of (A, B)): C[(A, B)] = (t map {i => i -> f(i)}).to[C]
    def mapTo[B](f: A => B)(implicit b: C of (A, B)): Map[A, B] = zipWith(f).toUniqueMap
    def whenNonEmpty[B](f: t.type => B): Option[B] = when(t.nonEmpty)(f(t))  // e.g. grades.whenNonEmpty(_.max)
    def collectFirst[B](f: PartialFunction[A, Option[B]]): Option[B] = t.view collect f collectFirst {case Some(x) => x}
    def toMutableMultiSet: Dict[A, Int] = {
      val c = map[A] to 0
      t.foreach(i => c(i) += 1)
      c
    }
    def toMultiSet: Map[A, Int] = toMutableMultiSet.toMap withDefaultValue 0
    def prefixSum(implicit n: Numeric[A]) = t.scanLeft(n.zero) {case (acc, i) => n.plus(acc, i)}
    def suffixSum(implicit n: Numeric[A]) = t.scanRight(n.zero) {case (i, acc) => n.plus(acc, i)}
  }
  implicit class ArrayExtensions[A <: AnyRef](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = java.util.Arrays.sort(a, from, until, cmp) //sort [from, until)
  }
  implicit class ArrayExtensions2[A](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = a.view(from, until).sorted.copyToArray(a, from)
  }
  implicit class SeqExtensions[A, C[X] <: Seq[X]](val s: C[A]) extends AnyVal {
    def isRotationOf(t: Seq[A]): Boolean = s ++ s containsSlice t
  }
  implicit class PairsExtensions[A, B, C[X] <: Traversable[X]](t: C[(A, B)]) {
    def toUniqueMap: Map[A, B] = t.groupByIdentifier(_._1).mapValues(_._2)
    def toMultiMap(implicit b: C of B): Map[A, C[B]] = t.groupBy(_._1).mapValues(_.map(_._2).to[C])
    def swap(implicit b: C of (B, A)): C[(B, A)] = t.map(_.swap).to[C]
  }
  implicit class MapExtensions[K, V, C[X, Y] <: Map[X, Y]](val m: C[K, V]) extends AnyVal {
    def invert: Map[V, Set[K]] = m.toSet[(K, V)].swap.toMultiMap
    def mapKeys[K2](f: K => K2): Map[K2, V] = m map {case (k, v) => f(k) -> v}
    def toMutable: Dict[K, V] = Dict.empty[K, V] ++ m
  }
  implicit class SetExtensions[A, C[A] <: Set[A]](val s: C[A]) extends AnyVal {
    def notContains(x: A): Boolean = !(s contains x)
    def toMutable = mutable.Set.empty[A] ++ s
  }
  implicit class SortedExtensions[A, C[A] <: collection.SortedSet[A]](val s: C[A]) extends AnyVal {
    def greaterThanOrEqualTo(a: A): Option[A] = s.from(a).headOption
    def lessThan(a: A): Option[A] = s.until(a).lastOption
  }
  implicit class IterableExtensions[A, C[A] <: Seq[A]](val s: C[A]) extends AnyVal {
    def findWithIndex(f: A => Boolean): Option[(A, Int)] = s.zipWithIndex find {case (a, _) => f(a)}
    def foldUntil[B](z: B)(f: (B, A) => B)(c: B => Boolean): Option[(B, Int)] = s.view.scanLeft(z)(f) findWithIndex c
  }
  implicit class BooleanExtensions(val x: Boolean) extends AnyVal {
    def to[A](implicit n: Numeric[A]) = if(x) n.one else n.zero
  }
  implicit class LongExtensions(val x: Long) extends AnyVal {
    def bitCount: Int = java.lang.Long.bitCount(x)
  }
  implicit class NumericExtensions[A](val x: A)(implicit n: Numeric[A]) {
    import Numeric.Implicits._
    def **(i: Int): A = if (i == 0) n.one else {
      val h = x ** (i/2)
      if (i%2 == 0) h * h else h * h * x
    }
    def absDiff(y: A) = (x - y).abs()
    def nonNegative: Option[A] = when(n.gteq(x, n.zero))(x)
    def whenNegative(f: => A): A = nonNegative getOrElse f   //e.g. students indexOf "Greg" whenNegative Int.MaxValue
  }
  implicit class IntegralExtensions[A](val x: A)(implicit n: Integral[A]) {
    import scala.collection.immutable.NumericRange, Integral.Implicits._
    def mod(y: A): A = x - ((x / y) * y) //(x/y)*y + (x mod y) == x
    def -->(y: A): NumericRange.Inclusive[A] = NumericRange.inclusive(n.min(x, y), n.max(x, y), n.one)
  }
  implicit def toPoint[A](p: (A, A))(implicit n: Numeric[A]) = new java.awt.geom.Point2D.Double(n.toDouble(p._1), n.toDouble(p._2))
  def desc[A: Ordering]: Ordering[A] = asc[A].reverse  //e.g. students.sortBy(_.height)(desc)
  def asc[A](implicit order: Ordering[A]): Ordering[A] = order
  def map[K] = new {
    def to[V](default: V): Dict[K, V] = Dict.empty[K, V] withDefaultValue default // also to(Dict.empty[K2, V])
  }
  def memoize[A, B](f: A => B): collection.Map[A, B] = new mutable.HashMap[A, B]() {
    override def apply(key: A) = getOrElseUpdate(key, f(key))
  }
  implicit class FuzzyDouble(x: Double)(implicit eps: Double = 1e-9) {
    def  >~(y: Double) = x > y + eps
    def >=~(y: Double) = x >= y + eps
    def  ~<(y: Double) = y >=~ x
    def ~=<(y: Double) = y >~ x
    def  ~=(y: Double) = (x absDiff y) <= eps
  }
  @inline def when[A](check: Boolean)(f: => A): Option[A] = if (check) Some(f) else None
  def repeat[U](n: Int)(f: => U): Unit = (1 to n).foreach(_ => f)
  type of[C[_], A] = scala.collection.generic.CanBuild[A, C[A]]
  val mod: Int = (1e9 + 7).toInt
}
/***********************************[Scala I/O]*********************************************/
import Utils._, java.io._, java.util.StringTokenizer

class IO(in: BufferedReader, out: BufferedWriter) extends PrintWriter(out, true) with Iterator[String] {
  def this(reader: Reader, writer: Writer) = this(new BufferedReader(reader), new BufferedWriter(writer))
  def this(in: InputStream, out: OutputStream) = this(new InputStreamReader(in), new OutputStreamWriter(out))

  private[this] val tokenizers = Iterator.continually(in.readLine()).takeWhile(_ != null).map(new StringTokenizer(_)).buffered

  @inline private[this] def tokenizer() = {
    while(tokenizers.nonEmpty && !tokenizers.head.hasMoreTokens) tokenizers.next()
    if (tokenizers.nonEmpty) Some(tokenizers.head) else None
  }

  def apply[A](implicit read: IO.Read[A]): A = read.apply(this)
  def apply[C[_], A: IO.Read](n: Int)(implicit b: C of A): C[A] = Iterator.fill(n)(apply).to[C]

  def till(delim: String): String = tokenizer().get.nextToken(delim)
  def tillEndOfLine(): String = till("\n\r")

  override def next() = tokenizer().get.nextToken()
  override def hasNext = tokenizer().nonEmpty

  var separator = " "
  private[this] var isNewLine = true

  def +=[A](x: A)(implicit write: IO.Write[A]): this.type = {
    write(this)(x)
    this
  }
  def ++=[A: IO.Write](xs: Traversable[A]): this.type = (this += xs.size) appendNewLine xs

  def appendNewLine[A: IO.Write](x: A): this.type = {
    println()
    this += x
  }

  override def print(obj: String) = {
    if (isNewLine) isNewLine = false else super.print(separator)
    super.print(obj)
  }
  override def println() = if (!isNewLine) {
    super.println()
    isNewLine = true
  }
  override def close() = {
    flush()
    in.close()
    super.close()
  }
}
object IO {
  class Read[A](val apply: IO => A) {
    def map[B](f: A => B): Read[B] = new Read(apply andThen f)
  }
  object Read {
    implicit def collection[C[_], A: Read](implicit b: C of A): Read[C[A]]         = new Read(r => r[C, A](r[Int]))
    implicit val string                                       : Read[String]       = new Read(_.next())
    implicit val char                                         : Read[Char]         = string.map(_.toTraversable.onlyElement)
    implicit val boolean                                      : Read[Boolean]      = string.map(_.toBoolean)
    implicit val int                                          : Read[Int]          = string.map(_.toInt)
    implicit val long                                         : Read[Long]         = string.map(_.toLong)
    implicit val bigInt                                       : Read[BigInt]       = string.map(BigInt(_))
    implicit val double                                       : Read[Double]       = string.map(_.toDouble)
    implicit val bigDecimal                                   : Read[BigDecimal]   = string.map(BigDecimal(_))
    implicit def tuple2[A: Read, B: Read]                     : Read[(A, B)]       = new Read(r => (r[A], r[B]))
    implicit def tuple3[A: Read, B: Read, C: Read]            : Read[(A, B, C)]    = new Read(r => (r[A], r[B], r[C]))
    implicit def tuple4[A: Read, B: Read, C: Read, D: Read]   : Read[(A, B, C, D)] = new Read(r => (r[A], r[B], r[C], r[D]))
  }
  trait Write[-A] {
    def apply(out: PrintWriter)(x: A): Unit
  }
  trait DefaultWrite {
    implicit def any[A]: Write[A] = Write(_.toString)
  }
  object Write extends DefaultWrite {
    def apply[A](f: A => String) = new Write[A] {
      override def apply(out: PrintWriter)(x: A) = out.print(f(x))
    }
    implicit val boolean: Write[Boolean] = Write(b => if (b) "YES" else "NO")
    implicit def tuple2[A, B]: Write[(A, B)] = Write {case (a, b) => s"$a $b"}
    implicit def array[A]: Write[Array[A]] = Write(_ mkString " ")
    implicit def iterable[A](implicit write: Write[A]): Write[Traversable[A]] = new Write[Traversable[A]] {
      override def apply(out: PrintWriter)(xs: Traversable[A]) = {
        xs foreach write(out)
        out.println()
      }
    }
  }
}

import Utils._, annotation.tailrec, collection.mutable, util._, control._, math.Ordering.Implicits._

object _676C extends CodeForcesApp {
  override def apply(io: IO) = {
    val (n, k, s) = io[(Int, Int, String)]

    val pas, pbs = Array.ofDim[Int](n + 1)

    s.indices foreach {i =>
      if (s(i) == 'a') {
        pas(i + 1) = pas(i) + 1
        pbs(i + 1) = pbs(i)
      } else {
        pas(i + 1) = pas(i)
        pbs(i + 1) = pbs(i) + 1
      }
    }

    var ans = 0

    @tailrec
    def solve(l: Int, r: Int): Unit = if (r <= n) {
      if(pas(r) - pas(l) <= k || pbs(r) - pbs(l) <= k) {
        ans = ans max (r - l)
        solve(l, r + 1)
      } else {
        solve(l + 1, r)
      }
    }

    solve(0, 0)

    io += ans
  }
}
/****************************[Ignore Template Below]****************************************/
trait CodeForcesApp {
  lazy val isOnlineJudge: Boolean = sys.props.get("ONLINE_JUDGE").exists(_.toBoolean)
  def debug(x: Any): Unit = if (!isOnlineJudge) println(x)
  def apply(io: IO): io.type
  def main(args: Array[String]): Unit = this(new IO(System.in, System.out)).close()
}
object Utils {
  import scala.collection.mutable, mutable.{Map => Dict}
  implicit class GenericExtensions[A](val a: A) extends AnyVal {
    def partialMatch[B](f: PartialFunction[A, B]): Option[B] = f lift a
  }
  implicit class TraversableExtensions[A, C[X] <: Traversable[X]](val t: C[A]) extends AnyVal {
    def onlyElement: A = t.head.ensuring(t.size == 1)
    def groupByIdentifier[K](f: A => K): Map[K, A] = t.groupBy(f).mapValues(_.onlyElement)
    def duplicates(implicit b: C of A): C[A] = {
      val elems = mutable.Set.empty[A]
      (t collect {case i if !elems.add(i) => i}).to[C]
    }
    def sumWith[B](f: A => B)(implicit n: Numeric[B]): B = t.foldLeft(n.zero) {case (p, i) => n.plus(p, f(i))}
    def zipWith[B](f: A => B)(implicit b: C of (A, B)): C[(A, B)] = (t map {i => i -> f(i)}).to[C]
    def mapTo[B](f: A => B)(implicit b: C of (A, B)): Map[A, B] = zipWith(f).toUniqueMap
    def whenNonEmpty[B](f: t.type => B): Option[B] = when(t.nonEmpty)(f(t))  // e.g. grades.whenNonEmpty(_.max)
    def collectFirst[B](f: PartialFunction[A, Option[B]]): Option[B] = t.view collect f collectFirst {case Some(x) => x}
    def toMutableMultiSet: Dict[A, Int] = {
      val c = map[A] to 0
      t.foreach(i => c(i) += 1)
      c
    }
    def toMultiSet: Map[A, Int] = toMutableMultiSet.toMap withDefaultValue 0
    def prefixSum(implicit n: Numeric[A]) = t.scanLeft(n.zero) {case (acc, i) => n.plus(acc, i)}
    def suffixSum(implicit n: Numeric[A]) = t.scanRight(n.zero) {case (i, acc) => n.plus(acc, i)}
  }
  implicit class ArrayExtensions[A <: AnyRef](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = java.util.Arrays.sort(a, from, until, cmp) //sort [from, until)
  }
  implicit class ArrayExtensions2[A](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = a.view(from, until).sorted.copyToArray(a, from)
  }
  implicit class SeqExtensions[A, C[X] <: Seq[X]](val s: C[A]) extends AnyVal {
    def isRotationOf(t: Seq[A]): Boolean = s ++ s containsSlice t
  }
  implicit class PairsExtensions[A, B, C[X] <: Traversable[X]](t: C[(A, B)]) {
    def toUniqueMap: Map[A, B] = t.groupByIdentifier(_._1).mapValues(_._2)
    def toMultiMap(implicit b: C of B): Map[A, C[B]] = t.groupBy(_._1).mapValues(_.map(_._2).to[C])
    def swap(implicit b: C of (B, A)): C[(B, A)] = t.map(_.swap).to[C]
  }
  implicit class MapExtensions[K, V, C[X, Y] <: Map[X, Y]](val m: C[K, V]) extends AnyVal {
    def invert: Map[V, Set[K]] = m.toSet[(K, V)].swap.toMultiMap
    def mapKeys[K2](f: K => K2): Map[K2, V] = m map {case (k, v) => f(k) -> v}
    def toMutable: Dict[K, V] = Dict.empty[K, V] ++ m
  }
  implicit class SetExtensions[A, C[A] <: Set[A]](val s: C[A]) extends AnyVal {
    def notContains(x: A): Boolean = !(s contains x)
    def toMutable = mutable.Set.empty[A] ++ s
  }
  implicit class SortedExtensions[A, C[A] <: collection.SortedSet[A]](val s: C[A]) extends AnyVal {
    def greaterThanOrEqualTo(a: A): Option[A] = s.from(a).headOption
    def lessThan(a: A): Option[A] = s.until(a).lastOption
  }
  implicit class IterableExtensions[A, C[A] <: Seq[A]](val s: C[A]) extends AnyVal {
    def findWithIndex(f: A => Boolean): Option[(A, Int)] = s.zipWithIndex find {case (a, _) => f(a)}
    def foldUntil[B](z: B)(f: (B, A) => B)(c: B => Boolean): Option[(B, Int)] = s.view.scanLeft(z)(f) findWithIndex c
  }
  implicit class BooleanExtensions(val x: Boolean) extends AnyVal {
    def to[A](implicit n: Numeric[A]) = if(x) n.one else n.zero
  }
  implicit class LongExtensions(val x: Long) extends AnyVal {
    def bitCount: Int = java.lang.Long.bitCount(x)
  }
  implicit class NumericExtensions[A](val x: A)(implicit n: Numeric[A]) {
    import Numeric.Implicits._
    def **(i: Int): A = if (i == 0) n.one else {
      val h = x ** (i/2)
      if (i%2 == 0) h * h else h * h * x
    }
    def absDiff(y: A) = (x - y).abs()
    def nonNegative: Option[A] = when(n.gteq(x, n.zero))(x)
    def whenNegative(f: => A): A = nonNegative getOrElse f   //e.g. students indexOf "Greg" whenNegative Int.MaxValue
  }
  implicit class IntegralExtensions[A](val x: A)(implicit n: Integral[A]) {
    import scala.collection.immutable.NumericRange, Integral.Implicits._
    def mod(y: A): A = x - ((x / y) * y) //(x/y)*y + (x mod y) == x
    def -->(y: A): NumericRange.Inclusive[A] = NumericRange.inclusive(n.min(x, y), n.max(x, y), n.one)
  }
  implicit def toPoint[A](p: (A, A))(implicit n: Numeric[A]) = new java.awt.geom.Point2D.Double(n.toDouble(p._1), n.toDouble(p._2))
  def desc[A: Ordering]: Ordering[A] = asc[A].reverse  //e.g. students.sortBy(_.height)(desc)
  def asc[A](implicit order: Ordering[A]): Ordering[A] = order
  def map[K] = new {
    def to[V](default: V): Dict[K, V] = Dict.empty[K, V] withDefaultValue default // also to(Dict.empty[K2, V])
  }
  def memoize[A, B](f: A => B): collection.Map[A, B] = new mutable.HashMap[A, B]() {
    override def apply(key: A) = getOrElseUpdate(key, f(key))
  }
  implicit class FuzzyDouble(x: Double)(implicit eps: Double = 1e-9) {
    def  >~(y: Double) = x > y + eps
    def >=~(y: Double) = x >= y + eps
    def  ~<(y: Double) = y >=~ x
    def ~=<(y: Double) = y >~ x
    def  ~=(y: Double) = (x absDiff y) <= eps
  }
  @inline def when[A](check: Boolean)(f: => A): Option[A] = if (check) Some(f) else None
  def repeat[U](n: Int)(f: => U): Unit = (1 to n).foreach(_ => f)
  type of[C[_], A] = scala.collection.generic.CanBuild[A, C[A]]
  val mod: Int = (1e9 + 7).toInt
}
/***********************************[Scala I/O]*********************************************/
import Utils._, java.io._, java.util.StringTokenizer

class IO(in: BufferedReader, out: BufferedWriter) extends PrintWriter(out, true) with Iterator[String] {
  def this(reader: Reader, writer: Writer) = this(new BufferedReader(reader), new BufferedWriter(writer))
  def this(in: InputStream, out: OutputStream) = this(new InputStreamReader(in), new OutputStreamWriter(out))

  private[this] val tokenizers = Iterator.continually(in.readLine()).takeWhile(_ != null).map(new StringTokenizer(_)).buffered

  @inline private[this] def tokenizer() = {
    while(tokenizers.nonEmpty && !tokenizers.head.hasMoreTokens) tokenizers.next()
    if (tokenizers.nonEmpty) Some(tokenizers.head) else None
  }

  def apply[A](implicit read: IO.Read[A]): A = read.apply(this)
  def apply[C[_], A: IO.Read](n: Int)(implicit b: C of A): C[A] = Iterator.fill(n)(apply).to[C]

  def till(delim: String): String = tokenizer().get.nextToken(delim)
  def tillEndOfLine(): String = till("\n\r")

  override def next() = tokenizer().get.nextToken()
  override def hasNext = tokenizer().nonEmpty

  var separator = " "
  private[this] var isNewLine = true

  def +=[A](x: A)(implicit write: IO.Write[A]): this.type = {
    write(this)(x)
    this
  }
  def ++=[A: IO.Write](xs: Traversable[A]): this.type = (this += xs.size) appendNewLine xs

  def appendNewLine[A: IO.Write](x: A): this.type = {
    println()
    this += x
  }

  override def print(obj: String) = {
    if (isNewLine) isNewLine = false else super.print(separator)
    super.print(obj)
  }
  override def println() = if (!isNewLine) {
    super.println()
    isNewLine = true
  }
  override def close() = {
    flush()
    in.close()
    super.close()
  }
}
object IO {
  class Read[A](val apply: IO => A) {
    def map[B](f: A => B): Read[B] = new Read(apply andThen f)
  }
  object Read {
    implicit def collection[C[_], A: Read](implicit b: C of A): Read[C[A]]         = new Read(r => r[C, A](r[Int]))
    implicit val string                                       : Read[String]       = new Read(_.next())
    implicit val char                                         : Read[Char]         = string.map(_.toTraversable.onlyElement)
    implicit val boolean                                      : Read[Boolean]      = string.map(_.toBoolean)
    implicit val int                                          : Read[Int]          = string.map(_.toInt)
    implicit val long                                         : Read[Long]         = string.map(_.toLong)
    implicit val bigInt                                       : Read[BigInt]       = string.map(BigInt(_))
    implicit val double                                       : Read[Double]       = string.map(_.toDouble)
    implicit val bigDecimal                                   : Read[BigDecimal]   = string.map(BigDecimal(_))
    implicit def tuple2[A: Read, B: Read]                     : Read[(A, B)]       = new Read(r => (r[A], r[B]))
    implicit def tuple3[A: Read, B: Read, C: Read]            : Read[(A, B, C)]    = new Read(r => (r[A], r[B], r[C]))
    implicit def tuple4[A: Read, B: Read, C: Read, D: Read]   : Read[(A, B, C, D)] = new Read(r => (r[A], r[B], r[C], r[D]))
  }
  trait Write[-A] {
    def apply(out: PrintWriter)(x: A): Unit
  }
  trait DefaultWrite {
    implicit def any[A]: Write[A] = Write(_.toString)
  }
  object Write extends DefaultWrite {
    def apply[A](f: A => String) = new Write[A] {
      override def apply(out: PrintWriter)(x: A) = out.print(f(x))
    }
    implicit val boolean: Write[Boolean] = Write(b => if (b) "YES" else "NO")
    implicit def tuple2[A, B]: Write[(A, B)] = Write {case (a, b) => s"$a $b"}
    implicit def array[A]: Write[Array[A]] = Write(_ mkString " ")
    implicit def iterable[A](implicit write: Write[A]): Write[Traversable[A]] = new Write[Traversable[A]] {
      override def apply(out: PrintWriter)(xs: Traversable[A]) = {
        xs foreach write(out)
        out.println()
      }
    }
  }
}

import Utils._, annotation.tailrec, collection.mutable, util._, control._, math.Ordering.Implicits._

object _676C extends CodeForcesApp {
  override def apply(io: IO) = {
    val (n, k, s) = io[(Int, Int, String)]

    val pas, pbs = Array.ofDim[Int](n + 1)
    s.indices foreach {i =>
      pas(i + 1) = pas(i) + (s(i) == 'a').to[Int]
      pbs(i + 1) = pbs(i) + (s(i) == 'b').to[Int]
    }

    def solve(l: Int, r: Int): Option[Int] = {
      when(pas(r) - pas(l) <= k || pbs(r) - pbs(l) <= k) {
        r - l
      }
    }

    io += twoPointer(n + 1)(solve).get
  }

  def twoPointer[A: Ordering](n: Int)(f: (Int, Int) => Option[A]): Option[A] = {
    def run(l: Int, r: Int): Option[A] = if(r == n) {
      None
    } else {
      f(l, r) match {
        case None if l < r => run(l + 1, r)
        case v => (run(l, r + 1) ++ v).whenNonEmpty(_.max)
      }
    }
    run(0, 0)
  }
}
/****************************[Ignore Template Below]****************************************/
trait CodeForcesApp {
  lazy val isOnlineJudge: Boolean = sys.props.get("ONLINE_JUDGE").exists(_.toBoolean)
  def debug(x: Any): Unit = if (!isOnlineJudge) println(x)
  def apply(io: IO): io.type
  def main(args: Array[String]): Unit = this(new IO(System.in, System.out)).close()
}
object Utils {
  import scala.collection.mutable, mutable.{Map => Dict}
  implicit class GenericExtensions[A](val a: A) extends AnyVal {
    def partialMatch[B](f: PartialFunction[A, B]): Option[B] = f lift a
  }
  implicit class TraversableExtensions[A, C[X] <: Traversable[X]](val t: C[A]) extends AnyVal {
    def onlyElement: A = t.head.ensuring(t.size == 1)
    def groupByIdentifier[K](f: A => K): Map[K, A] = t.groupBy(f).mapValues(_.onlyElement)
    def duplicates(implicit b: C of A): C[A] = {
      val elems = mutable.Set.empty[A]
      (t collect {case i if !elems.add(i) => i}).to[C]
    }
    def sumWith[B](f: A => B)(implicit n: Numeric[B]): B = t.foldLeft(n.zero) {case (p, i) => n.plus(p, f(i))}
    def zipWith[B](f: A => B)(implicit b: C of (A, B)): C[(A, B)] = (t map {i => i -> f(i)}).to[C]
    def mapTo[B](f: A => B)(implicit b: C of (A, B)): Map[A, B] = zipWith(f).toUniqueMap
    def whenNonEmpty[B](f: t.type => B): Option[B] = when(t.nonEmpty)(f(t))  // e.g. grades.whenNonEmpty(_.max)
    def collectFirst[B](f: PartialFunction[A, Option[B]]): Option[B] = t.view collect f collectFirst {case Some(x) => x}
    def toMutableMultiSet: Dict[A, Int] = {
      val c = map[A] to 0
      t.foreach(i => c(i) += 1)
      c
    }
    def toMultiSet: Map[A, Int] = toMutableMultiSet.toMap withDefaultValue 0
  }
  implicit class ArrayExtensions[A <: AnyRef](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = java.util.Arrays.sort(a, from, until, cmp) //sort [from, until)
  }
  implicit class ArrayExtensions2[A](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = a.view(from, until).sorted.copyToArray(a, from)
  }
  implicit class SeqExtensions[A, C[X] <: Seq[X]](val s: C[A]) extends AnyVal {
    def isRotationOf(t: Seq[A]): Boolean = s ++ s containsSlice t
  }
  implicit class PairsExtensions[A, B, C[X] <: Traversable[X]](t: C[(A, B)]) {
    def toUniqueMap: Map[A, B] = t.groupByIdentifier(_._1).mapValues(_._2)
    def toMultiMap(implicit b: C of B): Map[A, C[B]] = t.groupBy(_._1).mapValues(_.map(_._2).to[C])
    def swap(implicit b: C of (B, A)): C[(B, A)] = t.map(_.swap).to[C]
  }
  implicit class MapExtensions[K, V, C[X, Y] <: Map[X, Y]](val m: C[K, V]) extends AnyVal {
    def invert: Map[V, Set[K]] = m.toSet[(K, V)].swap.toMultiMap
    def mapKeys[K2](f: K => K2): Map[K2, V] = m map {case (k, v) => f(k) -> v}
    def toMutable: Dict[K, V] = Dict.empty[K, V] ++ m
  }
  implicit class SetExtensions[A, C[A] <: Set[A]](val s: C[A]) extends AnyVal {
    def notContains(x: A): Boolean = !(s contains x)
    def toMutable = mutable.Set.empty[A] ++ s
  }
  implicit class IterableExtensions[A, C[A] <: Seq[A]](val s: C[A]) extends AnyVal {
    def findWithIndex(f: A => Boolean): Option[(A, Int)] = s.zipWithIndex find {case (a, _) => f(a)}
    def foldUntil[B](z: B)(f: (B, A) => B)(c: B => Boolean): Option[(B, Int)] = s.view.scanLeft(z)(f) findWithIndex c
  }
  implicit class BooleanExtensions(val x: Boolean) extends AnyVal {
    def to[A](implicit n: Numeric[A]) = if(x) n.one else n.zero
  }
  implicit class LongExtensions(val x: Long) extends AnyVal {
    def bitCount: Int = java.lang.Long.bitCount(x)
  }
  implicit class NumericExtensions[A](val x: A)(implicit n: Numeric[A]) {
    import Numeric.Implicits._
    def **(i: Int): A = if (i == 0) n.one else {
      val h = x ** (i/2)
      if (i%2 == 0) h * h else h * h * x
    }
    def distance(y: A) = (x - y).abs()
    def nonNegative: Option[A] = when(n.gteq(x, n.zero))(x)
    def whenNegative(f: => A): A = nonNegative getOrElse f   //e.g. students indexOf "Greg" whenNegative Int.MaxValue
  }
  implicit class IntegralExtensions[A](val x: A)(implicit n: Integral[A]) {
    import scala.collection.immutable.NumericRange, Integral.Implicits._
    def mod(y: A): A = x - ((x / y) * y) //(x/y)*y + (x mod y) == x
    def -->(y: A): NumericRange.Inclusive[A] = NumericRange.inclusive(n.min(x, y), n.max(x, y), n.one)
  }
  implicit def toPoint[A](p: (A, A))(implicit n: Numeric[A]) = new java.awt.geom.Point2D.Double(n.toDouble(p._1), n.toDouble(p._2))
  def desc[A: Ordering]: Ordering[A] = asc[A].reverse  //e.g. students.sortBy(_.height)(desc)
  def asc[A](implicit order: Ordering[A]): Ordering[A] = order
  def map[K] = new {
    def to[V](default: V): Dict[K, V] = Dict.empty[K, V] withDefaultValue default // also to(Dict.empty[K2, V])
  }
  def memoize[A, B](f: A => B): collection.Map[A, B] = new mutable.HashMap[A, B]() {
    override def apply(key: A) = getOrElseUpdate(key, f(key))
  }
  implicit class FuzzyDouble(val x: Double) extends AnyVal {
    def  >~(y: Double) = x > y + eps
    def >=~(y: Double) = x >= y + eps
    def  ~<(y: Double) = y >=~ x
    def ~=<(y: Double) = y >~ x
    def  ~=(y: Double) = (x distance y) <= eps
  }
  @inline def when[A](check: Boolean)(f: => A): Option[A] = if (check) Some(f) else None
  def repeat[U](n: Int)(f: => U): Unit = (1 to n).foreach(_ => f)
  type of[C[_], A] = scala.collection.generic.CanBuild[A, C[A]]
  val mod: Int = (1e9 + 7).toInt
  val eps: Double = 1e-9
}
/***********************************[Scala I/O]*********************************************/
import Utils._, java.io._, java.util.StringTokenizer

class IO(in: BufferedReader, out: BufferedWriter) extends PrintWriter(out, true) with Iterator[String] {
  def this(reader: Reader, writer: Writer) = this(new BufferedReader(reader), new BufferedWriter(writer))
  def this(in: InputStream, out: OutputStream) = this(new InputStreamReader(in), new OutputStreamWriter(out))

  private[this] val tokenizers = Iterator.continually(in.readLine()).takeWhile(_ != null).map(new StringTokenizer(_)).buffered

  @inline private[this] def tokenizer() = {
    while(tokenizers.nonEmpty && !tokenizers.head.hasMoreTokens) tokenizers.next()
    if (tokenizers.nonEmpty) Some(tokenizers.head) else None
  }

  def apply[A](implicit read: IO.Read[A]): A = read.apply(this)
  def apply[C[_], A: IO.Read](n: Int)(implicit b: C of A): C[A] = Iterator.fill(n)(apply).to[C]

  def till(delim: String): String = tokenizer().get.nextToken(delim)
  def tillEndOfLine(): String = till("\n\r")

  override def next() = tokenizer().get.nextToken()
  override def hasNext = tokenizer().nonEmpty

  var separator = " "
  private[this] var isNewLine = true

  def +=[A](x: A)(implicit write: IO.Write[A]): this.type = {
    write(this)(x)
    this
  }
  def ++=[A: IO.Write](xs: Traversable[A]): this.type = (this += xs.size) appendNewLine xs

  def appendNewLine[A: IO.Write](x: A): this.type = {
    println()
    this += x
  }

  override def print(obj: String) = {
    if (isNewLine) isNewLine = false else super.print(separator)
    super.print(obj)
  }
  override def println() = if (!isNewLine) {
    super.println()
    isNewLine = true
  }
  override def close() = {
    flush()
    in.close()
    super.close()
  }
}
object IO {
  class Read[A](val apply: IO => A) {
    def map[B](f: A => B): Read[B] = new Read(apply andThen f)
  }
  object Read {
    implicit def collection[C[_], A: Read](implicit b: C of A): Read[C[A]]         = new Read(r => r[C, A](r[Int]))
    implicit val string                                       : Read[String]       = new Read(_.next())
    implicit val char                                         : Read[Char]         = string.map(_.toTraversable.onlyElement)
    implicit val boolean                                      : Read[Boolean]      = string.map(_.toBoolean)
    implicit val int                                          : Read[Int]          = string.map(_.toInt)
    implicit val long                                         : Read[Long]         = string.map(_.toLong)
    implicit val bigInt                                       : Read[BigInt]       = string.map(BigInt(_))
    implicit val double                                       : Read[Double]       = string.map(_.toDouble)
    implicit val bigDecimal                                   : Read[BigDecimal]   = string.map(BigDecimal(_))
    implicit def tuple2[A: Read, B: Read]                     : Read[(A, B)]       = new Read(r => (r[A], r[B]))
    implicit def tuple3[A: Read, B: Read, C: Read]            : Read[(A, B, C)]    = new Read(r => (r[A], r[B], r[C]))
    implicit def tuple4[A: Read, B: Read, C: Read, D: Read]   : Read[(A, B, C, D)] = new Read(r => (r[A], r[B], r[C], r[D]))
  }
  trait Write[-A] {
    def apply(out: PrintWriter)(x: A): Unit
  }
  trait DefaultWrite {
    implicit def any[A]: Write[A] = Write(_.toString)
  }
  object Write extends DefaultWrite {
    def apply[A](f: A => String) = new Write[A] {
      override def apply(out: PrintWriter)(x: A) = out.print(f(x))
    }
    implicit val boolean: Write[Boolean] = Write(b => if (b) "YES" else "NO")
    implicit def tuple2[A, B]: Write[(A, B)] = Write {case (a, b) => s"$a $b"}
    implicit def array[A]: Write[Array[A]] = Write(_ mkString " ")
    implicit def iterable[A](implicit write: Write[A]): Write[Traversable[A]] = new Write[Traversable[A]] {
      override def apply(out: PrintWriter)(xs: Traversable[A]) = {
        xs foreach write(out)
        out.println()
      }
    }
  }
}

import Utils._, annotation.tailrec, collection.mutable, util._, control._, math.Ordering.Implicits._

object _676C extends CodeForcesApp {
  override def apply(io: IO) = {
    val (n, k, s) = io[(Int, Int, String)]

    val pas, pbs = Array.ofDim[Int](n + 1)
    s.indices foreach {i =>
      pas(i + 1) = pas(i) + (s(i) == 'a').to[Int]
      pbs(i + 1) = pbs(i) + (s(i) == 'b').to[Int]
    }

    def isOk(l: Int, r: Int) = pas(r) - pas(l) <= k || pbs(r) - pbs(l) <= k
    val ans = twoPointer(n + 1)(isOk).maxBy{case (x, y) => y - x}

    io += (ans._2 - ans._1)
  }

  /**
    * Two pointer algorithm
    * O(2*n)
    *
    * @param n
    * @param f
    *          f must be monotonic i.e. j is a super-interval of i then f(j) => f(i)
    *                             anf also if !f(i) then for all
    * @return
    *         List of all intervals in [0, n) at which f is defined
    */
  def twoPointer(n: Int)(f: (Int, Int) => Boolean): Vector[(Int, Int)] = {
    def run(l: Int, r: Int): Vector[(Int, Int)] = if (r == n) {
      Vector.empty
    } else if (f(l, r)) {
      run(l, r + 1) :+ (l -> r)
    } else if (l < r) {
      run(l + 1, r)
    } else {
      run(l, r + 1)
    }
    run(0, 0)
  }
}
/****************************[Ignore Template Below]****************************************/
trait CodeForcesApp {
  lazy val isOnlineJudge: Boolean = sys.props.get("ONLINE_JUDGE").exists(_.toBoolean)
  def debug(x: Any): Unit = if (!isOnlineJudge) println(x)
  def apply(io: IO): io.type
  def main(args: Array[String]): Unit = this(new IO(System.in, System.out)).close()
}
object Utils {
  import scala.collection.mutable, mutable.{Map => Dict}
  implicit class GenericExtensions[A](val a: A) extends AnyVal {
    def partialMatch[B](f: PartialFunction[A, B]): Option[B] = f lift a
  }
  implicit class TraversableExtensions[A, C[X] <: Traversable[X]](val t: C[A]) extends AnyVal {
    def onlyElement: A = t.head.ensuring(t.size == 1)
    def groupByIdentifier[K](f: A => K): Map[K, A] = t.groupBy(f).mapValues(_.onlyElement)
    def duplicates(implicit b: C of A): C[A] = {
      val elems = mutable.Set.empty[A]
      (t collect {case i if !elems.add(i) => i}).to[C]
    }
    def sumWith[B](f: A => B)(implicit n: Numeric[B]): B = t.foldLeft(n.zero) {case (p, i) => n.plus(p, f(i))}
    def zipWith[B](f: A => B)(implicit b: C of (A, B)): C[(A, B)] = (t map {i => i -> f(i)}).to[C]
    def mapTo[B](f: A => B)(implicit b: C of (A, B)): Map[A, B] = zipWith(f).toUniqueMap
    def whenNonEmpty[B](f: t.type => B): Option[B] = when(t.nonEmpty)(f(t))  // e.g. grades.whenNonEmpty(_.max)
    def collectFirst[B](f: PartialFunction[A, Option[B]]): Option[B] = t.view collect f collectFirst {case Some(x) => x}
    def toMutableMultiSet: Dict[A, Int] = {
      val c = map[A] to 0
      t.foreach(i => c(i) += 1)
      c
    }
    def toMultiSet: Map[A, Int] = toMutableMultiSet.toMap withDefaultValue 0
  }
  implicit class ArrayExtensions[A <: AnyRef](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = java.util.Arrays.sort(a, from, until, cmp) //sort [from, until)
  }
  implicit class ArrayExtensions2[A](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = a.view(from, until).sorted.copyToArray(a, from)
  }
  implicit class SeqExtensions[A, C[X] <: Seq[X]](val s: C[A]) extends AnyVal {
    def isRotationOf(t: Seq[A]): Boolean = s ++ s containsSlice t
  }
  implicit class PairsExtensions[A, B, C[X] <: Traversable[X]](t: C[(A, B)]) {
    def toUniqueMap: Map[A, B] = t.groupByIdentifier(_._1).mapValues(_._2)
    def toMultiMap(implicit b: C of B): Map[A, C[B]] = t.groupBy(_._1).mapValues(_.map(_._2).to[C])
    def swap(implicit b: C of (B, A)): C[(B, A)] = t.map(_.swap).to[C]
  }
  implicit class MapExtensions[K, V, C[X, Y] <: Map[X, Y]](val m: C[K, V]) extends AnyVal {
    def invert: Map[V, Set[K]] = m.toSet[(K, V)].swap.toMultiMap
    def mapKeys[K2](f: K => K2): Map[K2, V] = m map {case (k, v) => f(k) -> v}
    def toMutable: Dict[K, V] = Dict.empty[K, V] ++ m
  }
  implicit class SetExtensions[A, C[A] <: Set[A]](val s: C[A]) extends AnyVal {
    def notContains(x: A): Boolean = !(s contains x)
    def toMutable = mutable.Set.empty[A] ++ s
  }
  implicit class IterableExtensions[A, C[A] <: Seq[A]](val s: C[A]) extends AnyVal {
    def findWithIndex(f: A => Boolean): Option[(A, Int)] = s.zipWithIndex find {case (a, _) => f(a)}
    def foldUntil[B](z: B)(f: (B, A) => B)(c: B => Boolean): Option[(B, Int)] = s.view.scanLeft(z)(f) findWithIndex c
  }
  implicit class BooleanExtensions(val x: Boolean) extends AnyVal {
    def to[A](implicit n: Numeric[A]) = if(x) n.one else n.zero
  }
  implicit class LongExtensions(val x: Long) extends AnyVal {
    def bitCount: Int = java.lang.Long.bitCount(x)
  }
  implicit class NumericExtensions[A](val x: A)(implicit n: Numeric[A]) {
    import Numeric.Implicits._
    def **(i: Int): A = if (i == 0) n.one else {
      val h = x ** (i/2)
      if (i%2 == 0) h * h else h * h * x
    }
    def distance(y: A) = (x - y).abs()
    def nonNegative: Option[A] = when(n.gteq(x, n.zero))(x)
    def whenNegative(f: => A): A = nonNegative getOrElse f   //e.g. students indexOf "Greg" whenNegative Int.MaxValue
  }
  implicit class IntegralExtensions[A](val x: A)(implicit n: Integral[A]) {
    import scala.collection.immutable.NumericRange, Integral.Implicits._
    def mod(y: A): A = x - ((x / y) * y) //(x/y)*y + (x mod y) == x
    def -->(y: A): NumericRange.Inclusive[A] = NumericRange.inclusive(n.min(x, y), n.max(x, y), n.one)
  }
  implicit def toPoint[A](p: (A, A))(implicit n: Numeric[A]) = new java.awt.geom.Point2D.Double(n.toDouble(p._1), n.toDouble(p._2))
  def desc[A: Ordering]: Ordering[A] = asc[A].reverse  //e.g. students.sortBy(_.height)(desc)
  def asc[A](implicit order: Ordering[A]): Ordering[A] = order
  def map[K] = new {
    def to[V](default: V): Dict[K, V] = Dict.empty[K, V] withDefaultValue default // also to(Dict.empty[K2, V])
  }
  def memoize[A, B](f: A => B): collection.Map[A, B] = new mutable.HashMap[A, B]() {
    override def apply(key: A) = getOrElseUpdate(key, f(key))
  }
  implicit class FuzzyDouble(val x: Double) extends AnyVal {
    def  >~(y: Double) = x > y + eps
    def >=~(y: Double) = x >= y + eps
    def  ~<(y: Double) = y >=~ x
    def ~=<(y: Double) = y >~ x
    def  ~=(y: Double) = (x distance y) <= eps
  }
  @inline def when[A](check: Boolean)(f: => A): Option[A] = if (check) Some(f) else None
  def repeat[U](n: Int)(f: => U): Unit = (1 to n).foreach(_ => f)
  type of[C[_], A] = scala.collection.generic.CanBuild[A, C[A]]
  val mod: Int = (1e9 + 7).toInt
  val eps: Double = 1e-9
}
/***********************************[Scala I/O]*********************************************/
import Utils._, java.io._, java.util.StringTokenizer

class IO(in: BufferedReader, out: BufferedWriter) extends PrintWriter(out, true) with Iterator[String] {
  def this(reader: Reader, writer: Writer) = this(new BufferedReader(reader), new BufferedWriter(writer))
  def this(in: InputStream, out: OutputStream) = this(new InputStreamReader(in), new OutputStreamWriter(out))

  private[this] val tokenizers = Iterator.continually(in.readLine()).takeWhile(_ != null).map(new StringTokenizer(_)).buffered

  @inline private[this] def tokenizer() = {
    while(tokenizers.nonEmpty && !tokenizers.head.hasMoreTokens) tokenizers.next()
    if (tokenizers.nonEmpty) Some(tokenizers.head) else None
  }

  def apply[A](implicit read: IO.Read[A]): A = read.apply(this)
  def apply[C[_], A: IO.Read](n: Int)(implicit b: C of A): C[A] = Iterator.fill(n)(apply).to[C]

  def till(delim: String): String = tokenizer().get.nextToken(delim)
  def tillEndOfLine(): String = till("\n\r")

  override def next() = tokenizer().get.nextToken()
  override def hasNext = tokenizer().nonEmpty

  var separator = " "
  private[this] var isNewLine = true

  def +=[A](x: A)(implicit write: IO.Write[A]): this.type = {
    write(this)(x)
    this
  }
  def ++=[A: IO.Write](xs: Traversable[A]): this.type = (this += xs.size) appendNewLine xs

  def appendNewLine[A: IO.Write](x: A): this.type = {
    println()
    this += x
  }

  override def print(obj: String) = {
    if (isNewLine) isNewLine = false else super.print(separator)
    super.print(obj)
  }
  override def println() = if (!isNewLine) {
    super.println()
    isNewLine = true
  }
  override def close() = {
    flush()
    in.close()
    super.close()
  }
}
object IO {
  class Read[A](val apply: IO => A) {
    def map[B](f: A => B): Read[B] = new Read(apply andThen f)
  }
  object Read {
    implicit def collection[C[_], A: Read](implicit b: C of A): Read[C[A]]         = new Read(r => r[C, A](r[Int]))
    implicit val string                                       : Read[String]       = new Read(_.next())
    implicit val char                                         : Read[Char]         = string.map(_.toTraversable.onlyElement)
    implicit val boolean                                      : Read[Boolean]      = string.map(_.toBoolean)
    implicit val int                                          : Read[Int]          = string.map(_.toInt)
    implicit val long                                         : Read[Long]         = string.map(_.toLong)
    implicit val bigInt                                       : Read[BigInt]       = string.map(BigInt(_))
    implicit val double                                       : Read[Double]       = string.map(_.toDouble)
    implicit val bigDecimal                                   : Read[BigDecimal]   = string.map(BigDecimal(_))
    implicit def tuple2[A: Read, B: Read]                     : Read[(A, B)]       = new Read(r => (r[A], r[B]))
    implicit def tuple3[A: Read, B: Read, C: Read]            : Read[(A, B, C)]    = new Read(r => (r[A], r[B], r[C]))
    implicit def tuple4[A: Read, B: Read, C: Read, D: Read]   : Read[(A, B, C, D)] = new Read(r => (r[A], r[B], r[C], r[D]))
  }
  trait Write[-A] {
    def apply(out: PrintWriter)(x: A): Unit
  }
  trait DefaultWrite {
    implicit def any[A]: Write[A] = Write(_.toString)
  }
  object Write extends DefaultWrite {
    def apply[A](f: A => String) = new Write[A] {
      override def apply(out: PrintWriter)(x: A) = out.print(f(x))
    }
    implicit val boolean: Write[Boolean] = Write(b => if (b) "YES" else "NO")
    implicit def tuple2[A, B]: Write[(A, B)] = Write {case (a, b) => s"$a $b"}
    implicit def array[A]: Write[Array[A]] = Write(_ mkString " ")
    implicit def iterable[A](implicit write: Write[A]): Write[Traversable[A]] = new Write[Traversable[A]] {
      override def apply(out: PrintWriter)(xs: Traversable[A]) = {
        xs foreach write(out)
        out.println()
      }
    }
  }
}

import Utils._, annotation.tailrec, collection.mutable, util._, control._, math.Ordering.Implicits._

object _676C extends CodeForcesApp {
  override def apply(io: IO) = {
    val (n, k, s) = io[(Int, Int, String)]

    val pas, pbs = Array.ofDim[Int](n + 1)
    s.indices foreach {i =>
      pas(i + 1) = pas(i) + (s(i) == 'a').to[Int]
      pbs(i + 1) = pbs(i) + (s(i) == 'b').to[Int]
    }

    def isOk(l: Int, r: Int) = pas(r) - pas(l) <= k || pbs(r) - pbs(l) <= k
    val Some((l, r)) = twoPointer(n + 1)(isOk)

    io += r - l
  }

  def twoPointer(n: Int)(f: (Int, Int) => Boolean): Option[(Int, Int)] = {
    def run(l: Int, r: Int): Option[(Int, Int)] = if(r == n) {
      None
    } else {
      val isValid = f(l, r)
      if (!isValid && l < r) {
        run(l + 1, r)
      } else {
        (run(l, r + 1) ++ when(isValid)(l -> r)).whenNonEmpty(_.maxBy { case (x, y) => y - x })
      }
    }
    run(0, 0)
  }
}
/****************************[Ignore Template Below]****************************************/
trait CodeForcesApp {
  lazy val isOnlineJudge: Boolean = sys.props.get("ONLINE_JUDGE").exists(_.toBoolean)
  def debug(x: Any): Unit = if (!isOnlineJudge) println(x)
  def apply(io: IO): io.type
  def main(args: Array[String]): Unit = this(new IO(System.in, System.out)).close()
}
object Utils {
  import scala.collection.mutable, mutable.{Map => Dict}
  implicit class GenericExtensions[A](val a: A) extends AnyVal {
    def partialMatch[B](f: PartialFunction[A, B]): Option[B] = f lift a
  }
  implicit class TraversableExtensions[A, C[X] <: Traversable[X]](val t: C[A]) extends AnyVal {
    def onlyElement: A = t.head.ensuring(t.size == 1)
    def groupByIdentifier[K](f: A => K): Map[K, A] = t.groupBy(f).mapValues(_.onlyElement)
    def duplicates(implicit b: C of A): C[A] = {
      val elems = mutable.Set.empty[A]
      (t collect {case i if !elems.add(i) => i}).to[C]
    }
    def sumWith[B](f: A => B)(implicit n: Numeric[B]): B = t.foldLeft(n.zero) {case (p, i) => n.plus(p, f(i))}
    def zipWith[B](f: A => B)(implicit b: C of (A, B)): C[(A, B)] = (t map {i => i -> f(i)}).to[C]
    def mapTo[B](f: A => B)(implicit b: C of (A, B)): Map[A, B] = zipWith(f).toUniqueMap
    def whenNonEmpty[B](f: t.type => B): Option[B] = when(t.nonEmpty)(f(t))  // e.g. grades.whenNonEmpty(_.max)
    def collectFirst[B](f: PartialFunction[A, Option[B]]): Option[B] = t.view collect f collectFirst {case Some(x) => x}
    def toMutableMultiSet: Dict[A, Int] = {
      val c = map[A] to 0
      t.foreach(i => c(i) += 1)
      c
    }
    def toMultiSet: Map[A, Int] = toMutableMultiSet.toMap withDefaultValue 0
  }
  implicit class ArrayExtensions[A <: AnyRef](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = java.util.Arrays.sort(a, from, until, cmp) //sort [from, until)
  }
  implicit class ArrayExtensions2[A](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = a.view(from, until).sorted.copyToArray(a, from)
  }
  implicit class SeqExtensions[A, C[X] <: Seq[X]](val s: C[A]) extends AnyVal {
    def isRotationOf(t: Seq[A]): Boolean = s ++ s containsSlice t
  }
  implicit class PairsExtensions[A, B, C[X] <: Traversable[X]](t: C[(A, B)]) {
    def toUniqueMap: Map[A, B] = t.groupByIdentifier(_._1).mapValues(_._2)
    def toMultiMap(implicit b: C of B): Map[A, C[B]] = t.groupBy(_._1).mapValues(_.map(_._2).to[C])
    def swap(implicit b: C of (B, A)): C[(B, A)] = t.map(_.swap).to[C]
  }
  implicit class MapExtensions[K, V, C[X, Y] <: Map[X, Y]](val m: C[K, V]) extends AnyVal {
    def invert: Map[V, Set[K]] = m.toSet[(K, V)].swap.toMultiMap
    def mapKeys[K2](f: K => K2): Map[K2, V] = m map {case (k, v) => f(k) -> v}
    def toMutable: Dict[K, V] = Dict.empty[K, V] ++ m
  }
  implicit class SetExtensions[A, C[A] <: Set[A]](val s: C[A]) extends AnyVal {
    def notContains(x: A): Boolean = !(s contains x)
    def toMutable = mutable.Set.empty[A] ++ s
  }
  implicit class IterableExtensions[A, C[A] <: Seq[A]](val s: C[A]) extends AnyVal {
    def findWithIndex(f: A => Boolean): Option[(A, Int)] = s.zipWithIndex find {case (a, _) => f(a)}
    def foldUntil[B](z: B)(f: (B, A) => B)(c: B => Boolean): Option[(B, Int)] = s.view.scanLeft(z)(f) findWithIndex c
  }
  implicit class BooleanExtensions(val x: Boolean) extends AnyVal {
    def to[A](implicit n: Numeric[A]) = if(x) n.one else n.zero
  }
  implicit class LongExtensions(val x: Long) extends AnyVal {
    def bitCount: Int = java.lang.Long.bitCount(x)
  }
  implicit class NumericExtensions[A](val x: A)(implicit n: Numeric[A]) {
    import Numeric.Implicits._
    def **(i: Int): A = if (i == 0) n.one else {
      val h = x ** (i/2)
      if (i%2 == 0) h * h else h * h * x
    }
    def distance(y: A) = (x - y).abs()
    def nonNegative: Option[A] = when(n.gteq(x, n.zero))(x)
    def whenNegative(f: => A): A = nonNegative getOrElse f   //e.g. students indexOf "Greg" whenNegative Int.MaxValue
  }
  implicit class IntegralExtensions[A](val x: A)(implicit n: Integral[A]) {
    import scala.collection.immutable.NumericRange, Integral.Implicits._
    def mod(y: A): A = x - ((x / y) * y) //(x/y)*y + (x mod y) == x
    def -->(y: A): NumericRange.Inclusive[A] = NumericRange.inclusive(n.min(x, y), n.max(x, y), n.one)
  }
  implicit def toPoint[A](p: (A, A))(implicit n: Numeric[A]) = new java.awt.geom.Point2D.Double(n.toDouble(p._1), n.toDouble(p._2))
  def desc[A: Ordering]: Ordering[A] = asc[A].reverse  //e.g. students.sortBy(_.height)(desc)
  def asc[A](implicit order: Ordering[A]): Ordering[A] = order
  def map[K] = new {
    def to[V](default: V): Dict[K, V] = Dict.empty[K, V] withDefaultValue default // also to(Dict.empty[K2, V])
  }
  def memoize[A, B](f: A => B): collection.Map[A, B] = new mutable.HashMap[A, B]() {
    override def apply(key: A) = getOrElseUpdate(key, f(key))
  }
  implicit class FuzzyDouble(val x: Double) extends AnyVal {
    def  >~(y: Double) = x > y + eps
    def >=~(y: Double) = x >= y + eps
    def  ~<(y: Double) = y >=~ x
    def ~=<(y: Double) = y >~ x
    def  ~=(y: Double) = (x distance y) <= eps
  }
  @inline def when[A](check: Boolean)(f: => A): Option[A] = if (check) Some(f) else None
  def repeat[U](n: Int)(f: => U): Unit = (1 to n).foreach(_ => f)
  type of[C[_], A] = scala.collection.generic.CanBuild[A, C[A]]
  val mod: Int = (1e9 + 7).toInt
  val eps: Double = 1e-9
}
/***********************************[Scala I/O]*********************************************/
import Utils._, java.io._, java.util.StringTokenizer

class IO(in: BufferedReader, out: BufferedWriter) extends PrintWriter(out, true) with Iterator[String] {
  def this(reader: Reader, writer: Writer) = this(new BufferedReader(reader), new BufferedWriter(writer))
  def this(in: InputStream, out: OutputStream) = this(new InputStreamReader(in), new OutputStreamWriter(out))

  private[this] val tokenizers = Iterator.continually(in.readLine()).takeWhile(_ != null).map(new StringTokenizer(_)).buffered

  @inline private[this] def tokenizer() = {
    while(tokenizers.nonEmpty && !tokenizers.head.hasMoreTokens) tokenizers.next()
    if (tokenizers.nonEmpty) Some(tokenizers.head) else None
  }

  def apply[A](implicit read: IO.Read[A]): A = read.apply(this)
  def apply[C[_], A: IO.Read](n: Int)(implicit b: C of A): C[A] = Iterator.fill(n)(apply).to[C]

  def till(delim: String): String = tokenizer().get.nextToken(delim)
  def tillEndOfLine(): String = till("\n\r")

  override def next() = tokenizer().get.nextToken()
  override def hasNext = tokenizer().nonEmpty

  var separator = " "
  private[this] var isNewLine = true

  def +=[A](x: A)(implicit write: IO.Write[A]): this.type = {
    write(this)(x)
    this
  }
  def ++=[A: IO.Write](xs: Traversable[A]): this.type = (this += xs.size) appendNewLine xs

  def appendNewLine[A: IO.Write](x: A): this.type = {
    println()
    this += x
  }

  override def print(obj: String) = {
    if (isNewLine) isNewLine = false else super.print(separator)
    super.print(obj)
  }
  override def println() = if (!isNewLine) {
    super.println()
    isNewLine = true
  }
  override def close() = {
    flush()
    in.close()
    super.close()
  }
}
object IO {
  class Read[A](val apply: IO => A) {
    def map[B](f: A => B): Read[B] = new Read(apply andThen f)
  }
  object Read {
    implicit def collection[C[_], A: Read](implicit b: C of A): Read[C[A]]         = new Read(r => r[C, A](r[Int]))
    implicit val string                                       : Read[String]       = new Read(_.next())
    implicit val char                                         : Read[Char]         = string.map(_.toTraversable.onlyElement)
    implicit val boolean                                      : Read[Boolean]      = string.map(_.toBoolean)
    implicit val int                                          : Read[Int]          = string.map(_.toInt)
    implicit val long                                         : Read[Long]         = string.map(_.toLong)
    implicit val bigInt                                       : Read[BigInt]       = string.map(BigInt(_))
    implicit val double                                       : Read[Double]       = string.map(_.toDouble)
    implicit val bigDecimal                                   : Read[BigDecimal]   = string.map(BigDecimal(_))
    implicit def tuple2[A: Read, B: Read]                     : Read[(A, B)]       = new Read(r => (r[A], r[B]))
    implicit def tuple3[A: Read, B: Read, C: Read]            : Read[(A, B, C)]    = new Read(r => (r[A], r[B], r[C]))
    implicit def tuple4[A: Read, B: Read, C: Read, D: Read]   : Read[(A, B, C, D)] = new Read(r => (r[A], r[B], r[C], r[D]))
  }
  trait Write[-A] {
    def apply(out: PrintWriter)(x: A): Unit
  }
  trait DefaultWrite {
    implicit def any[A]: Write[A] = Write(_.toString)
  }
  object Write extends DefaultWrite {
    def apply[A](f: A => String) = new Write[A] {
      override def apply(out: PrintWriter)(x: A) = out.print(f(x))
    }
    implicit val boolean: Write[Boolean] = Write(b => if (b) "YES" else "NO")
    implicit def tuple2[A, B]: Write[(A, B)] = Write {case (a, b) => s"$a $b"}
    implicit def array[A]: Write[Array[A]] = Write(_ mkString " ")
    implicit def iterable[A](implicit write: Write[A]): Write[Traversable[A]] = new Write[Traversable[A]] {
      override def apply(out: PrintWriter)(xs: Traversable[A]) = {
        xs foreach write(out)
        out.println()
      }
    }
  }
}

import Utils._, annotation.tailrec, collection.mutable, util._, control._, math.Ordering.Implicits._

object _676C extends CodeForcesApp {
  override def apply(io: IO) = {
    val (n, k, s) = io[(Int, Int, String)]

    val pas, pbs = Array.ofDim[Int](n + 1)
    s.indices foreach {i =>
      pas(i + 1) = pas(i) + (s(i) == 'a').to[Int]
      pbs(i + 1) = pbs(i) + (s(i) == 'b').to[Int]
    }

    def isOk(l: Int, r: Int) = pas(r) - pas(l) <= k || pbs(r) - pbs(l) <= k
    val ans = twoPointer(n + 1)(isOk).map{case (x, y) => y - x}

    io += ans.max
  }

  def twoPointer(n: Int)(f: (Int, Int) => Boolean): Vector[(Int, Int)] = {
    def run(l: Int, r: Int): Vector[(Int, Int)] = r match {
      case `n` => Vector.empty
      case _ if f(l, r) => run(l, r + 1) :+ (l -> r)
      case _ => if (l < r) run(l + 1, r) else run(l, r + 1)
    }
    run(0, 0)
  }
}
/****************************[Ignore Template Below]****************************************/
trait CodeForcesApp {
  lazy val isOnlineJudge: Boolean = sys.props.get("ONLINE_JUDGE").exists(_.toBoolean)
  def debug(x: Any): Unit = if (!isOnlineJudge) println(x)
  def apply(io: IO): io.type
  def main(args: Array[String]): Unit = this(new IO(System.in, System.out)).close()
}
object Utils {
  import scala.collection.mutable, mutable.{Map => Dict}
  implicit class GenericExtensions[A](val a: A) extends AnyVal {
    def partialMatch[B](f: PartialFunction[A, B]): Option[B] = f lift a
  }
  implicit class TraversableExtensions[A, C[X] <: Traversable[X]](val t: C[A]) extends AnyVal {
    def onlyElement: A = t.head.ensuring(t.size == 1)
    def groupByIdentifier[K](f: A => K): Map[K, A] = t.groupBy(f).mapValues(_.onlyElement)
    def duplicates(implicit b: C of A): C[A] = {
      val elems = mutable.Set.empty[A]
      (t collect {case i if !elems.add(i) => i}).to[C]
    }
    def sumWith[B](f: A => B)(implicit n: Numeric[B]): B = t.foldLeft(n.zero) {case (p, i) => n.plus(p, f(i))}
    def zipWith[B](f: A => B)(implicit b: C of (A, B)): C[(A, B)] = (t map {i => i -> f(i)}).to[C]
    def mapTo[B](f: A => B)(implicit b: C of (A, B)): Map[A, B] = zipWith(f).toUniqueMap
    def whenNonEmpty[B](f: t.type => B): Option[B] = when(t.nonEmpty)(f(t))  // e.g. grades.whenNonEmpty(_.max)
    def collectFirst[B](f: PartialFunction[A, Option[B]]): Option[B] = t.view collect f collectFirst {case Some(x) => x}
    def toMutableMultiSet: Dict[A, Int] = {
      val c = map[A] to 0
      t.foreach(i => c(i) += 1)
      c
    }
    def toMultiSet: Map[A, Int] = toMutableMultiSet.toMap withDefaultValue 0
  }
  implicit class ArrayExtensions[A <: AnyRef](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = java.util.Arrays.sort(a, from, until, cmp) //sort [from, until)
  }
  implicit class ArrayExtensions2[A](val a: Array[A]) extends AnyVal {
    def sort(from: Int, until: Int)(implicit cmp: Ordering[A]): Unit = a.view(from, until).sorted.copyToArray(a, from)
  }
  implicit class SeqExtensions[A, C[X] <: Seq[X]](val s: C[A]) extends AnyVal {
    def isRotationOf(t: Seq[A]): Boolean = s ++ s containsSlice t
  }
  implicit class PairsExtensions[A, B, C[X] <: Traversable[X]](t: C[(A, B)]) {
    def toUniqueMap: Map[A, B] = t.groupByIdentifier(_._1).mapValues(_._2)
    def toMultiMap(implicit b: C of B): Map[A, C[B]] = t.groupBy(_._1).mapValues(_.map(_._2).to[C])
    def swap(implicit b: C of (B, A)): C[(B, A)] = t.map(_.swap).to[C]
  }
  implicit class MapExtensions[K, V, C[X, Y] <: Map[X, Y]](val m: C[K, V]) extends AnyVal {
    def invert: Map[V, Set[K]] = m.toSet[(K, V)].swap.toMultiMap
    def mapKeys[K2](f: K => K2): Map[K2, V] = m map {case (k, v) => f(k) -> v}
    def toMutable: Dict[K, V] = Dict.empty[K, V] ++ m
  }
  implicit class SetExtensions[A, C[A] <: Set[A]](val s: C[A]) extends AnyVal {
    def notContains(x: A): Boolean = !(s contains x)
    def toMutable = mutable.Set.empty[A] ++ s
  }
  implicit class IterableExtensions[A, C[A] <: Seq[A]](val s: C[A]) extends AnyVal {
    def findWithIndex(f: A => Boolean): Option[(A, Int)] = s.zipWithIndex find {case (a, _) => f(a)}
    def foldUntil[B](z: B)(f: (B, A) => B)(c: B => Boolean): Option[(B, Int)] = s.view.scanLeft(z)(f) findWithIndex c
  }
  implicit class BooleanExtensions(val x: Boolean) extends AnyVal {
    def to[A](implicit n: Numeric[A]) = if(x) n.one else n.zero
  }
  implicit class LongExtensions(val x: Long) extends AnyVal {
    def bitCount: Int = java.lang.Long.bitCount(x)
  }
  implicit class NumericExtensions[A](val x: A)(implicit n: Numeric[A]) {
    import Numeric.Implicits._
    def **(i: Int): A = if (i == 0) n.one else {
      val h = x ** (i/2)
      if (i%2 == 0) h * h else h * h * x
    }
    def distance(y: A) = (x - y).abs()
    def nonNegative: Option[A] = when(n.gteq(x, n.zero))(x)
    def whenNegative(f: => A): A = nonNegative getOrElse f   //e.g. students indexOf "Greg" whenNegative Int.MaxValue
  }
  implicit class IntegralExtensions[A](val x: A)(implicit n: Integral[A]) {
    import scala.collection.immutable.NumericRange, Integral.Implicits._
    def mod(y: A): A = x - ((x / y) * y) //(x/y)*y + (x mod y) == x
    def -->(y: A): NumericRange.Inclusive[A] = NumericRange.inclusive(n.min(x, y), n.max(x, y), n.one)
  }
  implicit def toPoint[A](p: (A, A))(implicit n: Numeric[A]) = new java.awt.geom.Point2D.Double(n.toDouble(p._1), n.toDouble(p._2))
  def desc[A: Ordering]: Ordering[A] = asc[A].reverse  //e.g. students.sortBy(_.height)(desc)
  def asc[A](implicit order: Ordering[A]): Ordering[A] = order
  def map[K] = new {
    def to[V](default: V): Dict[K, V] = Dict.empty[K, V] withDefaultValue default // also to(Dict.empty[K2, V])
  }
  def memoize[A, B](f: A => B): collection.Map[A, B] = new mutable.HashMap[A, B]() {
    override def apply(key: A) = getOrElseUpdate(key, f(key))
  }
  implicit class FuzzyDouble(val x: Double) extends AnyVal {
    def  >~(y: Double) = x > y + eps
    def >=~(y: Double) = x >= y + eps
    def  ~<(y: Double) = y >=~ x
    def ~=<(y: Double) = y >~ x
    def  ~=(y: Double) = (x distance y) <= eps
  }
  @inline def when[A](check: Boolean)(f: => A): Option[A] = if (check) Some(f) else None
  def repeat[U](n: Int)(f: => U): Unit = (1 to n).foreach(_ => f)
  type of[C[_], A] = scala.collection.generic.CanBuild[A, C[A]]
  val mod: Int = (1e9 + 7).toInt
  val eps: Double = 1e-9
}
/***********************************[Scala I/O]*********************************************/
import Utils._, java.io._, java.util.StringTokenizer

class IO(in: BufferedReader, out: BufferedWriter) extends PrintWriter(out, true) with Iterator[String] {
  def this(reader: Reader, writer: Writer) = this(new BufferedReader(reader), new BufferedWriter(writer))
  def this(in: InputStream, out: OutputStream) = this(new InputStreamReader(in), new OutputStreamWriter(out))

  private[this] val tokenizers = Iterator.continually(in.readLine()).takeWhile(_ != null).map(new StringTokenizer(_)).buffered

  @inline private[this] def tokenizer() = {
    while(tokenizers.nonEmpty && !tokenizers.head.hasMoreTokens) tokenizers.next()
    if (tokenizers.nonEmpty) Some(tokenizers.head) else None
  }

  def apply[A](implicit read: IO.Read[A]): A = read.apply(this)
  def apply[C[_], A: IO.Read](n: Int)(implicit b: C of A): C[A] = Iterator.fill(n)(apply).to[C]

  def till(delim: String): String = tokenizer().get.nextToken(delim)
  def tillEndOfLine(): String = till("\n\r")

  override def next() = tokenizer().get.nextToken()
  override def hasNext = tokenizer().nonEmpty

  var separator = " "
  private[this] var isNewLine = true

  def +=[A](x: A)(implicit write: IO.Write[A]): this.type = {
    write(this)(x)
    this
  }
  def ++=[A: IO.Write](xs: Traversable[A]): this.type = (this += xs.size) appendNewLine xs

  def appendNewLine[A: IO.Write](x: A): this.type = {
    println()
    this += x
  }

  override def print(obj: String) = {
    if (isNewLine) isNewLine = false else super.print(separator)
    super.print(obj)
  }
  override def println() = if (!isNewLine) {
    super.println()
    isNewLine = true
  }
  override def close() = {
    flush()
    in.close()
    super.close()
  }
}
object IO {
  class Read[A](val apply: IO => A) {
    def map[B](f: A => B): Read[B] = new Read(apply andThen f)
  }
  object Read {
    implicit def collection[C[_], A: Read](implicit b: C of A): Read[C[A]]         = new Read(r => r[C, A](r[Int]))
    implicit val string                                       : Read[String]       = new Read(_.next())
    implicit val char                                         : Read[Char]         = string.map(_.toTraversable.onlyElement)
    implicit val boolean                                      : Read[Boolean]      = string.map(_.toBoolean)
    implicit val int                                          : Read[Int]          = string.map(_.toInt)
    implicit val long                                         : Read[Long]         = string.map(_.toLong)
    implicit val bigInt                                       : Read[BigInt]       = string.map(BigInt(_))
    implicit val double                                       : Read[Double]       = string.map(_.toDouble)
    implicit val bigDecimal                                   : Read[BigDecimal]   = string.map(BigDecimal(_))
    implicit def tuple2[A: Read, B: Read]                     : Read[(A, B)]       = new Read(r => (r[A], r[B]))
    implicit def tuple3[A: Read, B: Read, C: Read]            : Read[(A, B, C)]    = new Read(r => (r[A], r[B], r[C]))
    implicit def tuple4[A: Read, B: Read, C: Read, D: Read]   : Read[(A, B, C, D)] = new Read(r => (r[A], r[B], r[C], r[D]))
  }
  trait Write[-A] {
    def apply(out: PrintWriter)(x: A): Unit
  }
  trait DefaultWrite {
    implicit def any[A]: Write[A] = Write(_.toString)
  }
  object Write extends DefaultWrite {
    def apply[A](f: A => String) = new Write[A] {
      override def apply(out: PrintWriter)(x: A) = out.print(f(x))
    }
    implicit val boolean: Write[Boolean] = Write(b => if (b) "YES" else "NO")
    implicit def tuple2[A, B]: Write[(A, B)] = Write {case (a, b) => s"$a $b"}
    implicit def array[A]: Write[Array[A]] = Write(_ mkString " ")
    implicit def iterable[A](implicit write: Write[A]): Write[Traversable[A]] = new Write[Traversable[A]] {
      override def apply(out: PrintWriter)(xs: Traversable[A]) = {
        xs foreach write(out)
        out.println()
      }
    }
  }
}

object Solution extends App {
  val in = io.Source.stdin.getLines()
  val Array(n, k) = in.next().split(' ').map(_.toInt)
  val line = in.next()
  val (at, _, _, bt, _, _) = line.indices.foldLeft((0, 0, k, 0, 0, k)) {
    case (att@(amax, acurrent, aleft, bmax, bcurrent, bleft), i) =>
//      println(att)
      val ch = line(i)
      if (ch == 'a') {
        if (bleft > 0)
          (Math.max(amax, acurrent + 1), acurrent + 1, aleft, Math.max(bmax, bcurrent + 1), bcurrent + 1, bleft - 1)
        else {
          var ni = i - bcurrent + 1
          while (ni > 0 && i - ni > 0 && line(i - ni) == 'a')
            ni -= 1
          if (ni < i  && i - ni > 0 && line(ni) == 'b')
            (Math.max(amax, acurrent + 1), acurrent + 1, aleft, Math.max(bmax, ni - 1), ni - 1, bleft)
          else
            (Math.max(amax, acurrent + 1), acurrent + 1, aleft, bmax, 0, k)
        }
      }
      else {
        if (aleft > 0)
          (Math.max(amax, acurrent + 1), acurrent + 1, aleft - 1, Math.max(bmax, bcurrent + 1), bcurrent + 1, bleft)
        else {
//          println("acurrent " + acurrent)
//          println("i = " + i)
          var ni = i - acurrent + 1
//          println("NI " + ni)
          while (ni > 0  && i - ni > 0 && line(i - ni) == 'b')
            ni -= 1
          if (ni < i && i - ni > 0 && line(i - ni) == 'a')
            (Math.max(amax, ni - 1), ni - 1, aleft, Math.max(bmax, bcurrent + 1), bcurrent + 1, bleft)
          else
            (amax, 0, k, Math.max(bmax, bcurrent + 1), bcurrent + 1, bleft)
        }
      }
  }
  println(Math.max(at, bt))
}


You have two positive integers $$$a$$$ and $$$b$$$.You can perform two kinds of operations:  $$$a = \lfloor \frac{a}{b} \rfloor$$$ (replace $$$a$$$ with the integer part of the division between $$$a$$$ and $$$b$$$)  $$$b=b+1$$$ (increase $$$b$$$ by $$$1$$$) Find the minimum number of operations required to make $$$a=0$$$.

The first line contains a single integer $$$t$$$ ($$$1 \le t \le 100$$$) — the number of test cases. The only line of the description of each test case contains two integers $$$a$$$, $$$b$$$ ($$$1 \le a,b \le 10^9$$$).

For each test case, print a single integer: the minimum number of operations required to make $$$a=0$$$.

NoteIn the first test case, one of the optimal solutions is:  Divide $$$a$$$ by $$$b$$$. After this operation $$$a = 4$$$ and $$$b = 2$$$.  Divide $$$a$$$ by $$$b$$$. After this operation $$$a = 2$$$ and $$$b = 2$$$.  Increase $$$b$$$. After this operation $$$a = 2$$$ and $$$b = 3$$$.  Divide $$$a$$$ by $$$b$$$. After this operation $$$a = 0$$$ and $$$b = 3$$$.

object CP {

  import InOut._
  def main(args: Array[String]): Unit = {
    for (_ <- 1 to nextInt) {
      solve()
    }
  }

  def solve(): Unit = {
    var a = nextLong
    var b = nextLong
    var ans = 10000L

    for (test <- b to b + 10) {
      var c = a
      var times = 0L
      while (c > 0 && test != 1 && c != test) {
        c = c / test
        times += 1
      }
      if (test != 1 && c != test) ans = math.min(ans, times + test - b)
    }
    println(ans)

  }

  final object InOut {
//    import java.io.{BufferedReader, FileInputStream, FileReader, FilterInputStream, FilterReader}
//    import scala.io.Source
//    val in = new BufferedReader(new FileReader("./src/main/scala/input.txt"))
    val in = new java.io.BufferedReader(new java.io.InputStreamReader(System.in))

    val out = new java.io.PrintWriter(System.out, false)
    private[this] var tokenizer: java.util.StringTokenizer = _
    def nextToken: String = {
      while (tokenizer == null || !tokenizer.hasMoreTokens)
        tokenizer = new java.util.StringTokenizer(in.readLine)
      tokenizer.nextToken
    }
    def nextInt = Integer.parseInt(nextToken)
    def nextLong = java.lang.Long.parseLong(nextToken)
    def nextBig = BigInt(nextToken)
    def nextInts(n: Int) = Array.fill(n) { nextInt }
    def nextLongs(n: Int) = Array.fill(n) { nextLong }
    def nextBigs(n: Int) = Array.fill(n) { nextBig }
    def nextLine = in.readLine
  }
}

object E {

  import InOut._
  def main(args: Array[String]): Unit = {
    for (_ <- 1 to nextInt) {
      solve()
    }
  }

  def solve(): Unit = {
    var a = nextLong
    var b = nextLong
    var ans = 10000L

    for (test <- b to b + 10) {
      var c = a
      var times = 0L
      while (c > 0 && test != 1 && c != test) {
        c = c / test
        times += 1
      }
      if (test != 1 && c != test) ans = math.min(ans, times + test - b)
    }
    println(ans)
  }

  final object InOut {
    val in = new java.io.BufferedReader(new java.io.InputStreamReader(System.in))
//    val in = new BufferedReader(new FileReader("./src/main/scala/input.txt"))

    val out = new java.io.PrintWriter(System.out, false)
    private[this] var tokenizer: java.util.StringTokenizer = _
    def nextToken: String = {
      while (tokenizer == null || !tokenizer.hasMoreTokens)
        tokenizer = new java.util.StringTokenizer(in.readLine)
      tokenizer.nextToken
    }
    def nextInt = Integer.parseInt(nextToken)
    def nextLong = java.lang.Long.parseLong(nextToken)
    def nextBig = BigInt(nextToken)
    def nextInts(n: Int) = Array.fill(n) { nextInt }
    def nextLongs(n: Int) = Array.fill(n) { nextLong }
    def nextBigs(n: Int) = Array.fill(n) { nextBig }
    def nextLine = in.readLine
  }
}

import java.io.BufferedReader
import java.io.ByteArrayInputStream
import java.io.InputStreamReader

object AAddandDivide {
  def solve(a: Int, b: Int): Int = {
    if (a < b) 1
    else if (a == b) {
      2
    } else {
      var min  = Int.MaxValue
      var lmin = Int.MaxValue - 1
      var i = if (b == 1) 1 else 0
      while (lmin <= min) {
        min = lmin
        var j = 1
        while (Math.pow(b + i, j) <= a) {
          j += 1
        }
        lmin = i + j
        i += 1
      }
      min
    }
  }

  def main(args: Array[String]): Unit = {
    val file = new BufferedReader(new InputStreamReader(System.in))
//        val file = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(
//          "6\n9 2\n1337 1\n1 1\n50000000 4\n991026972 997\n1234 5678".getBytes)))
//          "1\n50000000 4".getBytes)))
    val inputs = file.readLine.toInt
    var i = 0
    while (i < inputs) {
      val a::b::Nil = file.readLine.split(" ").map(_.toInt).toList
      println(solve(a, b))
      i += 1
    }
  }
}


You are a coach at your local university. There are $$$n$$$ students under your supervision, the programming skill of the $$$i$$$-th student is $$$a_i$$$.You have to create a team for a new programming competition. As you know, the more students some team has the more probable its victory is! So you have to create a team with the maximum number of students. But you also know that a team should be balanced. It means that the programming skill of each pair of students in a created team should differ by no more than $$$5$$$.Your task is to report the maximum possible number of students in a balanced team.

The first line of the input contains one integer $$$n$$$ ($$$1 \le n \le 2 \cdot 10^5$$$) — the number of students. The second line of the input contains $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$ ($$$1 \le a_i \le 10^9$$$), where $$$a_i$$$ is a programming skill of the $$$i$$$-th student.

Print one integer — the maximum possible number of students in a balanced team.

NoteIn the first example you can create a team with skills $$$[12, 17, 15]$$$.In the second example you can take all students in a team because their programming skills are equal.In the third example you can create a team consisting of a single student (and you cannot create a team consisting of at least two students).

object Main {
  def main(args: Array[String]): Unit = {
    val s = new Main()
    s.solve()
    s.out.flush()
  }
}

class Main {
  import java.io._
  import java.util.StringTokenizer

  import scala.collection.mutable
  import scala.util.Sorting
  import math.{abs, max, min}
  import mutable.{ArrayBuffer, ListBuffer}
  import scala.reflect.ClassTag

  val MOD = 1000000007
  val out = new PrintWriter(System.out)

  def solve(): Unit = {
    val N = ni()
    val A = na(N)
    sort(A)

    var ans = 0
    var r = 0
    REP(N) { l =>
      if (r < l) r = l
      while(r + 1 < N && A(r + 1) - A(l) <= 5) r += 1
      if (r < N && A(r) - A(l) <= 5) ans = max(ans, r - l + 1)
    }
    out.println(ans)
  }

  def sort(a: Array[Int]): Array[Int] = {
    val n = a.length
    REP(n) { i =>
      val j = scala.util.Random.nextInt(n - i) + i
      val tmp = a(i)
      a(i) = a(j)
      a(j) = tmp
    }
    Sorting.stableSort(a)
    a
  }

  private val oj = System.getenv("ATCODER_DEBUG") == null

  def DEBUG(f: => Unit): Unit = {
    if (!oj){ f }
  }

  def debug(as: Array[Boolean]): Unit = DEBUG {
    debug(as.map(x => if(x) "1" else "0").mkString)
  }

  def debug(as: Array[Int]): Unit = DEBUG {
    debug(as.mkString(" "))
  }

  def debug(as: Array[Long]): Unit = DEBUG {
    debug(as.mkString(" "))
  }

  def debug(s: => String): Unit = DEBUG {
    System.err.println(s)
  }

  def debugNum(num: => Long): Unit = DEBUG {
    System.err.println(num)
  }

  class InputReader(val stream: InputStream) {
    private val reader = new BufferedReader(new InputStreamReader(stream), 32768)
    private var tokenizer: StringTokenizer = _

    def next(): String = {
      while (tokenizer == null || !tokenizer.hasMoreTokens)
        tokenizer = new StringTokenizer(reader.readLine)
      tokenizer.nextToken
    }

    def nextInt(): Int = next().toInt
    def nextLong(): Long = next().toLong
    def nextChar(): Char = next().charAt(0)
  }
  val sc = new InputReader(System.in)
  def ni(): Int = sc.nextInt()
  def nl(): Long = sc.nextLong()
  def nc(): Char = sc.nextChar()
  def ns(): String = sc.next()
  def ns(n: Int): Array[Char] = ns().toCharArray
  def na(n: Int, offset: Int = 0): Array[Int] = map(n)(_ => ni() + offset)
  def na2(n: Int, offset: Int = 0): (Array[Int], Array[Int]) = {
    val A1, A2 = Array.ofDim[Int](n)
    REP(n) { i =>
      A1(i) = ni() + offset
      A2(i) = ni() + offset
    }
    (A1, A2)
  }
  def nm(n: Int, m: Int): Array[Array[Int]] = {
    val A = Array.ofDim[Int](n, m)
    REP(n) { i =>
      REP(m) { j =>
        A(i)(j) = ni()
      }
    }
    A
  }
  def nal(n: Int): Array[Long] = map(n)(_ => nl())
  def nm_c(n: Int, m: Int): Array[Array[Char]] = map(n) (_ => ns(m))
  def REP(n: Int, offset: Int = 0)(f: Int => Unit): Unit = {
    var i = offset
    val N = n + offset
    while(i < N) { f(i); i += 1 }
  }
  def REP_r(n: Int, offset: Int = 0)(f: Int => Unit): Unit = {
    var i = n - 1 + offset
    while(i >= offset) { f(i); i -= 1 }
  }

  def map[@specialized A: ClassTag](n: Int, offset: Int = 0)(f: Int => A): Array[A] = {
    val res = Array.ofDim[A](n)
    REP(n)(i => res(i) = f(i + offset))
    res
  }

  def sumL(as: Array[Int]): Long = {
    var s = 0L
    REP(as.length)(i => s += as(i))
    s
  }

  def cumSum(as: Array[Int]) = {
    val cum = Array.ofDim[Long](as.length + 1)
    REP(as.length) { i =>
      cum(i + 1) = cum(i) + as(i)
    }
    cum
  }
}

object C {
  import scala.collection.mutable
  def main(args: Array[String]){
    val n = readInt
    val skills = readLine().split(" ").map(_.toInt).sorted
    val max = 5
    var total = 0
    var best = 0
    var last = skills.head
    val using = mutable.SortedMap[Int, Int]()
    skills.foreach { s =>
      while(using.nonEmpty && s - using.head._1 > 5) {
      total -= using.head._2
      using -= using.head._1
    }
      total += 1
      if(!using.contains(s)) using(s) = 0
      using(s) += 1
      best = Math.max(best, total)
    }

    println(best)
  }
}

object C {
  import scala.collection.mutable
  def main(args: Array[String]){
    val n = readInt
    val skills = readLine().split(" ").map(_.toInt).sorted
    val max = 5
    var total = 0
    var best = 0
    var last = skills.head
    val using = mutable.SortedMap[Int, Int]()
    skills.foreach { s =>
      while(using.nonEmpty && s - using.head._1 > 5) {
      total -= using.head._2
      using -= using.head._1
    }
      total += 1
      if(!using.contains(s)) using(s) = 0
      using(s) += 1
    }

    println(total)
  }
}

object C {
  import scala.collection.mutable
  def main(args: Array[String]){
    val n = readInt
    val skills = readLine().split(" ").map(_.toInt).sorted
    val max = 5
    var total = 0
    var best = 0
    var last = skills.head
    val using = mutable.SortedSet[Int]()
    skills.foreach { s =>
      while(using.nonEmpty && s - using.head > 5) {
        using -= using.head
        total -= 1
      }
      total += 1
      using += s
    }

    println(total)
  }
}


Today, Yasser and Adel are at the shop buying cupcakes. There are $$$n$$$ cupcake types, arranged from $$$1$$$ to $$$n$$$ on the shelf, and there are infinitely many of each type. The tastiness of a cupcake of type $$$i$$$ is an integer $$$a_i$$$. There are both tasty and nasty cupcakes, so the tastiness can be positive, zero or negative.Yasser, of course, wants to try them all, so he will buy exactly one cupcake of each type.On the other hand, Adel will choose some segment $$$[l, r]$$$ $$$(1 \le l \le r \le n)$$$ that does not include all of cupcakes (he can't choose $$$[l, r] = [1, n]$$$) and buy exactly one cupcake of each of types $$$l, l + 1, \dots, r$$$.After that they will compare the total tastiness of the cupcakes each of them have bought. Yasser will be happy if the total tastiness of cupcakes he buys is strictly greater than the total tastiness of cupcakes Adel buys regardless of Adel's choice.For example, let the tastinesses of the cupcakes be $$$[7, 4, -1]$$$. Yasser will buy all of them, the total tastiness will be $$$7 + 4 - 1 = 10$$$. Adel can choose segments $$$[7], [4], [-1], [7, 4]$$$ or $$$[4, -1]$$$, their total tastinesses are $$$7, 4, -1, 11$$$ and $$$3$$$, respectively. Adel can choose segment with tastiness $$$11$$$, and as $$$10$$$ is not strictly greater than $$$11$$$, Yasser won't be happy :(Find out if Yasser will be happy after visiting the shop.

Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 10^4$$$). The description of the test cases follows. The first line of each test case contains $$$n$$$ ($$$2 \le n \le 10^5$$$). The second line of each test case contains $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$ ($$$-10^9 \le a_i \le 10^9$$$), where $$$a_i$$$ represents the tastiness of the $$$i$$$-th type of cupcake. It is guaranteed that the sum of $$$n$$$ over all test cases doesn't exceed $$$10^5$$$.

For each test case, print "YES", if the total tastiness of cupcakes Yasser buys will always be strictly greater than the total tastiness of cupcakes Adel buys regardless of Adel's choice. Otherwise, print "NO".

NoteIn the first example, the total tastiness of any segment Adel can choose is less than the total tastiness of all cupcakes.In the second example, Adel will choose the segment $$$[1, 2]$$$ with total tastiness $$$11$$$, which is not less than the total tastiness of all cupcakes, which is $$$10$$$.In the third example, Adel can choose the segment $$$[3, 3]$$$ with total tastiness of $$$5$$$. Note that Yasser's cupcakes' total tastiness is also $$$5$$$, so in that case, the total tastiness of Yasser's cupcakes isn't strictly greater than the total tastiness of Adel's cupcakes.

object Main {
    def main(args: Array[String]): Unit = {
        val t = readInt
        Iterator.fill(t)(f1).foldLeft(()){ case _ => () }
    }

    def f1(): Unit = {
        val n = readLong
        val a = readLine.split(" ").map(_.toLong)
        val (sum, l, r, list) = a.zipWithIndex.foldLeft((0L, 0L, 0L, Vector[(Long, Long, Long)]())){
            case ((sum, l, r, list), (x, i)) => {
                val newlist = if ((sum <= 0 || x <= 0) && l != r) list :+ (sum, l, r) else list
                if (sum > 0 && sum + x > 0) (sum + x, l, i + 1, newlist) else (x, i, i + 1, newlist)
            }
        }
        val x = a.sum
        if (((sum, l, r) +: list).forall{ case (s, l, r) => s < x || ( l == 0 && r == a.length) }) println("YES")
        else println("NO")
    }
}

import java.util.Scanner

object A extends App {
  val sc = new Scanner(System.in)

  val t = sc.nextInt

  (1 to t)
    .foreach(_ => {
      val n = sc.nextInt

      val arr = Array.tabulate(n)(_ => sc.nextLong)

      val a1 = arr.foldLeft((0L, true))((a,b) => {val t = a._1 + b; (t, a._2 && t > 0)})
      val a2 = arr.reverse.foldLeft((0L, true))((a,b) => {val t = a._1 + b; (t, a._2 && t > 0)})

      println(if (a1._2 && a2._2) "YES" else "NO")
    })

}

object Main {
    def main(args: Array[String]): Unit = {
        val t = readInt
        Iterator.fill(t)(f1).foldLeft(()){ case _ => () }
    }

    def f1(): Unit = {
        val n = readInt
        val a = readLine.split(" ").map(_.toInt)
        val (sum, l, r, list) = a.zipWithIndex.foldLeft((0, 0, 0, List[(Int, Int, Int)]())){
            case ((sum, l, r, list), (x, i)) => {
                val newlist = if ((sum <= 0 || x <= 0) && l != r) list :+ (sum, l, r) else list
                if (sum > 0 && sum + x > 0) (sum + x, l, i + 1, newlist) else (x, i, i + 1, newlist)
            }
        }
        val x = a.sum
        if (((sum, l, r) +: list).forall{ case (s, l, r) => s < x || ( l == 0 && r == a.length) }) println("YES")
        else println("NO")
    }
}

object Main {
    def main(args: Array[String]): Unit = {
        val t = readInt
        Iterator.fill(t)(f1).foldLeft(()){ case _ => () }
    }

    def f1(): Unit = {
        val n = readInt
        val a = readLine.split(" ").map(_.toInt)
        val (sum, l, r, list) = a.zipWithIndex.foldLeft((0, 0, 0, List[(Int, Int, Int)]())){
            case ((sum, l, r, list), (x, i)) => {
                val newlist = if (x <= 0 && l != r) list :+ (sum, l, r) else list
                if (sum + x > 0) (sum + x, l, i + 1, newlist) else (x, i, i + 1, newlist)
            }
        }
        val x = a.sum
        if (((sum, l, r) +: list).forall{ case (s, l, r) => s < x || ( l == 0 && r == a.length) }) println("YES")
        else println("NO")
    }
}

import java.util.Scanner

object A extends App {
  val sc = new Scanner(System.in)

  val t = sc.nextInt

  (1 to t)
    .foreach(_ => {
      val n = sc.nextInt

      val arr = Array.tabulate(n)(_ => sc.nextInt)

      val a1 = arr.foldLeft((0, true))((a,b) => {val t = a._1 + b; (t, a._2 && t > 0)})
      val a2 = arr.reverse.foldLeft((0, true))((a,b) => {val t = a._1 + b; (t, a._2 && t > 0)})

      println(if (a1._2 && a2._2) "YES" else "NO")
    })

}


Email address in Berland is a string of the form A@B, where A and B are arbitrary strings consisting of small Latin letters. Bob is a system administrator in «Bersoft» company. He keeps a list of email addresses of the company's staff. This list is as a large string, where all addresses are written in arbitrary order, separated by commas. The same address can be written more than once.Suddenly, because of unknown reasons, all commas in Bob's list disappeared. Now Bob has a string, where all addresses are written one after another without any separators, and there is impossible to determine, where the boundaries between addresses are. Unfortunately, on the same day his chief asked him to bring the initial list of addresses. Now Bob wants to disjoin addresses in some valid way. Help him to do that.

The first line contains the list of addresses without separators. The length of this string is between 1 and 200, inclusive. The string consists only from small Latin letters and characters «@».

If there is no list of the valid (according to the Berland rules) email addresses such that after removing all commas it coincides with the given string, output No solution. In the other case, output the list. The same address can be written in this list more than once. If there are several solutions, output any of them.

object Solution extends App {
  val in = io.Source.stdin.getLines()
  val line = in.next().split("@", -1)
  if (line.contains("") || line.length < 2 || line.drop(1).dropRight(1).exists(_.length == 1))
    println("No solution")
  else
    println(line.indices.flatMap{
      case (0) => List(line(0))
      case (i) if i == line.length - 1 => List(line(line.length - 1))
      case (i) => List(line(i).head, line(i).tail)
    }.grouped(2).map(_.mkString("@")).mkString(","))
}

import scala.io._
import scala.collection.mutable._
import java.util.StringTokenizer

object HelloWorld {

  def main(args: Array[String]): Unit = {
    var s = readLine;
    if (s.startsWith("@") || s.endsWith("@") || !s.contains("@")) {
      println("No solution");
      return;
    }
    var ss = s.split("@");
    var atCount = s.count(_.toChar == '@')
    if (ss.length - 1 != atCount) {
      println("No solution");
      return;
    }
    for (i <- 0 until ss.length) {
      if (i != 0 && i != ss.length - 1) {
        if (ss(i).length <= 1) {
          println("No solution");
          return;
        }
      }
    }
    var result = "";
    var prev = false;
    var atNumber = 0;
    for (e <- s) {
      result += e;
      if (prev && atNumber != atCount) {
        result += ",";
        prev = false;
      }
      if (e == '@') {
        atNumber += 1;
        prev = true;
      }
    }
    println(result);
  }

}

object Solution extends App {
  val in = io.Source.stdin.getLines()
  val line = in.next().split("@", -1)
  if (line.contains("") || line.drop(1).dropRight(1).exists(_.length == 1))
    println("No solution")
  else
    println(line.indices.flatMap{
      case (0) => List(line(0))
      case (i) if i == line.length - 1 => List(line(line.length - 1))
      case (i) => List(line(i).head, line(i).tail)
    }.grouped(2).map(_.mkString("@")).mkString(","))
}

import scala.io._
import scala.collection.mutable._
import java.util.StringTokenizer

object HelloWorld {

  def main(args: Array[String]): Unit = {
    var s = readLine;
    if (s.startsWith("@") || s.endsWith("@")) {
      println("No solution");
      return;
    }
    var ss = s.split("@");
    var atCount = s.count(_.toChar == '@')
    if (ss.length - 1 != atCount) {
      println("No solution");
      return;
    }
    for (i <- 0 until ss.length) {
      if (i != 0 && i != ss.length - 1) {
        if (ss(i).length <= 1) {
          println("No solution");
          return;
        }
      }
    }
    var result = "";
    var prev = false;
    var atNumber = 0;
    for (e <- s) {
      result += e;
      if (prev && atNumber != atCount) {
        result += ",";
        prev = false;
      }
      if (e == '@') {
        atNumber += 1;
        prev = true;
      }
    }
    println(result);
  }

}


One day Petya got a birthday present from his mom: a book called "The Legends and Myths of Graph Theory". From this book Petya learned about a hydra graph.A non-oriented graph is a hydra, if it has a structure, shown on the figure below. Namely, there are two nodes u and v connected by an edge, they are the hydra's chest and stomach, correspondingly. The chest is connected with h nodes, which are the hydra's heads. The stomach is connected with t nodes, which are the hydra's tails. Note that the hydra is a tree, consisting of h + t + 2 nodes.  Also, Petya's got a non-directed graph G, consisting of n nodes and m edges. Petya got this graph as a last year birthday present from his mom. Graph G contains no self-loops or multiple edges.Now Petya wants to find a hydra in graph G. Or else, to make sure that the graph doesn't have a hydra.

The first line contains four integers n, m, h, t (1 ≤ n, m ≤ 105, 1 ≤ h, t ≤ 100) — the number of nodes and edges in graph G, and the number of a hydra's heads and tails. Next m lines contain the description of the edges of graph G. The i-th of these lines contains two integers ai and bi (1 ≤ ai, bi ≤ n, a ≠ b) — the numbers of the nodes, connected by the i-th edge. It is guaranteed that graph G contains no self-loops and multiple edges. Consider the nodes of graph G numbered with integers from 1 to n.

If graph G has no hydra, print "NO" (without the quotes). Otherwise, in the first line print "YES" (without the quotes). In the second line print two integers — the numbers of nodes u and v. In the third line print h numbers — the numbers of the nodes that are the heads. In the fourth line print t numbers — the numbers of the nodes that are the tails. All printed numbers should be distinct. If there are multiple possible answers, you are allowed to print any of them.

NoteThe first sample is depicted on the picture below:

import java.util.Scanner
import scala.collection.JavaConverters._

object Main extends App {
  val sc = new java.util.Scanner(System.in)

  val n, m, h, t = sc.nextInt

  val es = Array.tabulate(m)(_ => (sc.nextInt(), sc.nextInt()))

  val vsp = Array.tabulate(n+1)(_ => (new java.util.HashSet[Int]()).asScala)

  es foreach { e =>
    vsp(e._1) += e._2
    vsp(e._2) += e._1
  }

  val vs = vsp

  def makeHydra(vh: Int, vt: Int): Boolean = {
    if (vs(vh).size > h && vs(vt).size > t && (vs(vh) ++ vs(vt)).size >= h + t + 2) {
      println("YES")
      println("%d %d".format(vh, vt))
      val cm = (vs(vh) & vs(vt)).toSeq
      val rh = (vs(vh) - vt -- cm).toSeq ++ cm ++ (vs(vt) - vh -- cm).toSeq
      println(rh.take(h).mkString(" "))
      println(rh.takeRight(t).mkString(" "))

      true
    } else false
  }

  es sortBy { case (src, dst) =>
    - (vs(src).size + vs(dst).size)
  } indexWhere { e =>
    makeHydra(e._1, e._2) || makeHydra(e._2, e._1)
  } match {
    case -1 => println("NO");
    case _ => Unit
  }
}

object Main extends App {
  import java.{util => ju}
  import scala.collection.JavaConverters._

  val sc = new ju.Scanner(System.in)

  val n, m, h, t = sc.nextInt

  val es = Array.tabulate(m)(_ => (sc.nextInt(), sc.nextInt()))

  val vsp = Array.tabulate(n+1)(_ => (new ju.HashSet[Int]()).asScala)

  es foreach { case (src, dst) =>
    vsp(src) += dst
    vsp(dst) += src
  }

  val vs = vsp

  def makeHydra(vh: Int, vt: Int): Boolean = {
    if (vs(vh).size > h && vs(vt).size > t && (vs(vh) ++ vs(vt)).size >= h + t + 2) {
      println("YES")
      println("%d %d".format(vh, vt))
      val cm = (vs(vh) & vs(vt)).toSeq
      val rh = (vs(vh) - vt -- cm).toSeq ++ cm ++ (vs(vt) - vh -- cm).toSeq
      println(rh.take(h).mkString(" "))
      println(rh.takeRight(t).mkString(" "))

      true
    } else false
  }

  es sortBy { case (src, dst) =>
    - (vs(src).size + vs(dst).size)
  } indexWhere { case (src, dst) =>
    makeHydra(src, dst) || makeHydra(dst, src)
  } match {
    case -1 => println("NO");
    case _ => Unit
  }
}

import java.util.Scanner
import scala.collection.mutable.ListBuffer

object Main extends App {
  val sc = new java.util.Scanner(System.in)

  val n, m, h, t = sc.nextInt

  val es = Array.tabulate(m)(_ => (sc.nextInt(), sc.nextInt()))

  val vsp = Array.tabulate(n+1)(_ => ListBuffer[Int]())

  es foreach { e =>
    vsp(e._1) += e._2
    vsp(e._2) += e._1
  }

  val vs = vsp.map(_.toSet)

  def makeHydra(vh: Int, vt: Int): Boolean = {
    if (vs(vh).size > h && vs(vt).size > t && (vs(vh) ++ vs(vt)).size >= h + t + 2) {
      println("YES")
      println("%d %d".format(vh, vt))
      val cm = (vs(vh) & vs(vt)).toSeq
      val rh = (vs(vh) - vt -- cm).toSeq ++ cm ++ (vs(vt) - vh -- cm).toSeq
      println(rh.take(h).mkString(" "))
      println(rh.takeRight(t).mkString(" "))

      true
    } else false
  }

  es sortBy { case (src, dst) =>
    - (vs(src).size + vs(dst).size)
  } indexWhere { e =>
    makeHydra(e._1, e._2) || makeHydra(e._2, e._1)
  } match {
    case -1 => println("NO");
    case _ => Unit
  }
}

import java.util.Scanner
import scala.collection.mutable.ListBuffer

object Main extends App {
  val sc = new java.util.Scanner(System.in)

  val n, m, h, t = sc.nextInt

  val es = Array.tabulate(m)(_ => (sc.nextInt(), sc.nextInt()))

  val vsp = Array.tabulate(n+1)(_ => ListBuffer[Int]())

  es foreach { e =>
    vsp(e._1) += e._2
    vsp(e._2) += e._1
  }

  val vs = vsp.map(_.toSet)

  def makeHydra(vh: Int, vt: Int): Boolean = {
    if (vs(vh).size > h && vs(vt).size > t && (vs(vh) ++ vs(vt)).size >= h + t + 2) {
      println("YES")
      println("%d %d".format(vh, vt))
      val cm = (vs(vh) & vs(vt)).toSeq
      val rh = (vs(vh) - vt -- cm).toSeq ++ cm
      val rt = cm.reverse ++ (vs(vt) - vh -- cm).toSeq
      println(rh.take(h).mkString(" "))
      println(rt.takeRight(t).mkString(" "))

      true
    } else false
  }

  es indexWhere { e =>
    makeHydra(e._1, e._2) || makeHydra(e._2, e._1)
  } match {
    case -1 => println("NO");
    case _ => Unit
  }
}

import java.util.Scanner
import scala.collection.mutable._

object Main extends App {
  val sc = new java.util.Scanner(System.in)

  val n, m, h, t = sc.nextInt

  val es = Array.tabulate(m)(_ => (sc.nextInt(), sc.nextInt()))

  val vs = Array.tabulate(n+1)(_ => Set[Int]())

  es foreach { e =>
    vs(e._1) += e._2
    vs(e._2) += e._1
  }

  def makeHydra(vh: Int, vt: Int): Boolean = {
    val cm = vs(vh) & vs(vt)
    if (vs(vh).size > h && vs(vt).size > t && vs(vh).size + vs(vt).size + cm.size >=  h + t + 2) {
      println("YES")
      println("%d %d".format(vh, vt))

      val rv = (vs(vh) - vt -- cm).toList ++ cm.toList ++ (vs(vt) - vh -- cm).toList

      println(rv.take(h).mkString(" "))
      println(rv.takeRight(t).mkString(" "))

      true
    } else false
  }

  es indexWhere { e =>
    makeHydra(e._1, e._2) || makeHydra(e._2, e._1)
  } match {
    case -1 => println("NO");
    case _ => Unit
  }
}

import java.util.Scanner
import scala.collection.mutable._

object Main extends App {
  val sc = new java.util.Scanner(System.in)

  val n, m, h, t = sc.nextInt

  val es = Array.tabulate(m)(_ => (sc.nextInt(), sc.nextInt()))

  val vs = Array.tabulate(n+1)(_ => Set[Int]())

  es foreach { e =>
    vs(e._1) += e._2
    vs(e._2) += e._1
  }

  def makeHydra(vh: Int, vt: Int): Boolean = {
    if (vs(vh).size > h && vs(vt).size > t && (vs(vh) ++ vs(vt)).size >= h + t + 2) {
      println("%d %d".format(vh, vt))

      val cm = vs(vh) & vs(vt)
      val rv = (vs(vh) - vt -- cm).toList ++ cm.toList ++ (vs(vt) - vh -- cm).toList

      println(rv.take(h).mkString(" "))
      println(rv.takeRight(t).mkString(" "))

      true
    } else false
  }

  es indexWhere { e =>
    makeHydra(e._1, e._2) || makeHydra(e._2, e._1)
  }
}

import java.util.Scanner
import scala.collection.mutable.ListBuffer

object Main extends App {
  val sc = new java.util.Scanner(System.in)

  val n, m, h, t = sc.nextInt

  val es = Array.tabulate(m)(_ => (sc.nextInt(), sc.nextInt()))

  val vsp = Array.tabulate(n+1)(_ => ListBuffer[Int]())

  es foreach { e =>
    vsp(e._1) += e._2
    vsp(e._2) += e._1
  }

  val vs = vsp.map(_.toSet)

  def makeHydra(vh: Int, vt: Int): Boolean = {
    if (vs(vh).size > h && vs(vt).size > t && (vs(vh) ++ vs(vt)).size >= h + t + 2) {
      println("YES")
      println("%d %d".format(vh, vt))
      return true

      val cm = (vs(vh) & vs(vt)).toArray
      val rh = (vs(vh) - vt -- cm)
      val rt = (vs(vt) - vh -- cm).take(t).toArray ++ cm.reverse.take(t)

      println(rh.take(h).mkString(" "))
      println(rt.take(t).mkString(" "))

      true
    } else false
  }

  es indexWhere { e =>
    makeHydra(e._1, e._2) || makeHydra(e._2, e._1)
  } match {
    case -1 => println("NO");
    case _ => Unit
  }
}