using System;

namespace temp
{
	class Program
	{
		public static void Main (string[] args)
		{
			int n = int.Parse(Console.ReadLine());
			string[] str = Console.ReadLine().Split(new char[]{' '},StringSplitOptions.RemoveEmptyEntries);
			int stk=0;
			int[] a = {0,0,0};
			for(int i=0;i<n;i++)
			{
				a[stk]+=int.Parse(str[i]);
				stk++;
				if(stk>2)
				{
					stk=0;
				}
			}
			if(a[0]>a[1] && a[0]>a[2])
			{
				Console.WriteLine("chest");
				return;
			}
			if(a[1]>a[0] && a[1]>a[2])
			{
				Console.WriteLine("biceps");
				return ;
			}
			Console.WriteLine("back");
			return;
		}
	}
}

using System;
using System.Linq;
using System.Collections.Generic;

namespace tren
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine()), chest = 0, biceps = 0, back = 0;
            List<int> mass = Console.ReadLine().Split(' ').Select(int.Parse).ToList();
            for (int i = 0; i < n; i++)
            {
                if (i % 3 == 0)
                {
                    chest += mass[i];
                    mass[i] = 0;
                }
            }
            for (int i = 0; i < mass.Count(); i++)
            {
                if (mass[i] == 0) mass.Remove(mass[i]);
            }

            for (int i = 0; i < mass.Count(); i++)
            {
                if (i % 2 == 0) biceps += mass[i];
                else back += mass[i];
            }
            if (biceps > chest && biceps > back) Console.Write("biceps");
            if (chest  > biceps && chest > back) Console.Write("chest");
            if (back > chest && back > biceps) Console.Write("back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ASM
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Int32.Parse(Console.ReadLine());
            int[] workout = Console.ReadLine().Split(' ').Select(x => Int32.Parse(x)).ToArray<int>();
            int chest = 0;
            int biceps = 0;
            int back = 0;

            for(int i = 0; i < n / 3; i++)
            {
                chest += workout[i*3];
                biceps += workout[i*3+1];
                back += workout[i*3+2];
            }

            if(n % 3 == 1)
                chest += workout[n - 1];
            else if(n%3 == 2)
            {
                chest += workout[n - 2];
                biceps += workout[n - 1];
            }

            if(chest > biceps && chest > back)
                Console.WriteLine("chest");
            else if (biceps > chest && biceps > back)
                Console.WriteLine("biceps");
            else if (back > chest && back > biceps)
                Console.WriteLine("back");
        }

    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace A.Greg_s_Workout
{
    class Program
    {
        static void Main(string[] args)
        {
            int Number = int.Parse(Console.ReadLine());
            string[] Exe = (Console.ReadLine()).Split(' ');
            int chest = 0, biceps = 0, back = 0;
            bool Chest = true, Biceps = false, Back = false;
            for (int i = 0; i < Number; i++)
            {
                if (Chest)
                {
                    chest+=int.Parse(Exe[i]);
                    Chest = false;
                    Biceps = true;
                }
                else if (Biceps)
                {
                    biceps+= int.Parse(Exe[i]);
                    Biceps = false;
                    Back = true;
                }
                else
                {
                    back+= int.Parse(Exe[i]);
                    Chest = true;
                    Back = false;
                }

            }
            if (chest > biceps && chest > back)
            {
                Console.WriteLine("chest");
            }
            else if (biceps > chest && biceps > back)
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.IO;
using System.Threading.Tasks;

namespace fun
{
    class Program
    {
        private static TextReader cin = Console.In;
        private static TextWriter cout = Console.Out;
        static void Main(string[] args)
        {
            string s = cin.ReadLine() ;
            int n = int.Parse(s.Split(' ')[0]);
            var t = Array.ConvertAll(cin.ReadLine().Split(' '), int.Parse);
            int a = 0, b = 0, c = 0 ;

            for (int i = 0; i < n; i++)
            {
                if (i % 3 == 0) a += t[i];
                if (i % 3 == 1) b += t[i];
                if (i % 3 == 2) c += t[i];
            }
            int m =Math.Max(a, Math.Max(b, c));
            cout.Write((m == a) ? "chest" : ((m == b) ? "biceps" : "back"));
            //cin.ReadLine();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    public class Program
    {
        public static void Main()
        {
            int days;
            int[] exercises;
            int[] type = new int[3];
            string[] body = { "chest", "biceps", "back" };

            days = Convert.ToInt32(Console.ReadLine());

            exercises = (Console.ReadLine().Split(' ')).Select(n => Convert.ToInt32(n)).ToArray();
            int j = 0;

            for (int i = 0; i < days; ++i)
            {
                type[j] += exercises[i];
                if (j == 2)
                    j = 0;
                else
                    ++j;
            }
            int Max = type.ToList().IndexOf(type.Max());

            Console.WriteLine(body[Max]);
        }
    }
}

using System;
using System.Linq;
class Program
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine());
        var a = Console.ReadLine().Split().Select(int.Parse).ToArray();
        var m = new int[3];
        for (int i = 0; i < n; i++)
        {
            m[i % 3] += a[i];
        }
        Console.WriteLine("{0}", new string[] { "chest", "biceps", "back" }[Array.IndexOf(m, m.Max())]);
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;

namespace SolvingAlgorithms
{
    class Program
    {
        static void Main(string[] args)
        {

            string input;
            input = Console.ReadLine();
            int n = Convert.ToInt32(input);
            input = Console.ReadLine();
            List<String> split = new List<string>(input.Split(' '));
            string current = "chest";
            int countChest = 0;
            int countBi = 0;
            int countBack = 0;

            while(split.Count>0)
            {
                int temp = Convert.ToInt32(split[0]);

                switch (current)
                {
                    case "chest": current = "biceps"; countChest += temp; break;
                    case "biceps": current = "back"; countBi += temp; break;
                    case "back": current = "chest"; countBack += temp; break;
                }
                split.RemoveAt(0);
            }

            if (countChest > countBi && countChest > countBack)
            {
                Console.WriteLine("chest");
            }
            else if (countBi > countChest && countBi > countBack)
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }
        }

    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Greg_s_Workout
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            string[] r = Console.ReadLine().Split(' ');
            int chest = 0;
            int biceps = 0;
            int back = 0;
            for (int i = 0; i < n; i++)
            {
                int a = int.Parse(r[i]);
                if (i % 3 == 0) chest += a;
                else if (i % 3 == 1) biceps += a;
                else back += a;
            }
            int max = Math.Max(chest, Math.Max(biceps, back));
            if (max == chest) Console.WriteLine("chest");
            else if (max == biceps) Console.WriteLine("biceps");
            else Console.WriteLine("back");
        }
    }
}

using System;

namespace AllProblems
{
    class Program
    {
        static void Main(string[] args)
        {
            _255A_GregsWorkout.Run();

        }
    }
    class _255A_GregsWorkout
    {
        public static void Run()
        {
            var n = byte.Parse(Console.ReadLine().Trim());
            var l = Console.ReadLine().Trim().Split(' ');

            var len = n > 3 ? 3 : n;
            var arr = new short[len];
            var ind = new short[len];

            for (byte i = 0; i < len; i++)
                ind[i] = i;

            for (byte i = 0; i < n; i++)
                arr[i%3] += byte.Parse(l[i]);

            Array.Sort(arr,ind);
            var m = new[] {"chest", "biceps", "back"};
            Console.WriteLine(m[ind[len - 1]]);
            Console.ReadLine();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text;
using System.Linq;
using System.IO;
using System.Globalization;
using System.Collections;
using System.Text.RegularExpressions;

namespace Task
{

    #region MyIo

    internal class MyIo : IDisposable
    {
        private readonly TextReader inputStream;
        private readonly TextWriter outputStream = Console.Out;

        private string[] tokens;
        private int pointer;

        public MyIo()
#if  LOCAL_TEST
            : this(new StreamReader("input.txt"))
#else
            : this(System.Console.In)
#endif
        {

        }

        public MyIo(TextReader inputStream)
        {
            this.inputStream = inputStream;
        }

        public char NextChar()
        {
            try
            {
                return (char)inputStream.Read();
            }
            catch (IOException)
            {
                return '\0';
            }
        }

        public string NextLine()
        {
            try
            {
                return inputStream.ReadLine();
            }
            catch (IOException)
            {
                return null;
            }
        }

        public string NextString()
        {
            try
            {
                while (tokens == null || pointer >= tokens.Length)
                {
                    tokens = (NextLine() + string.Empty).Split(new[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
                    pointer = 0;
                }
                return tokens[pointer++];
            }
            catch (IOException)
            {
                return null;
            }
        }

        public int NextInt()
        {
            return Next<int>();
        }

        public long NextLong()
        {
            return Next<long>();
        }

        public T Next<T>()
        {
            var t = typeof(T);

            if (t == typeof(char))
                return (T)(object)NextChar();

            object s = NextString();

            if (t == typeof(string))
                return (T)s;

            return (T)Convert.ChangeType(s, typeof(T));
        }

        public IEnumerable<T> NextWhile<T>(Predicate<T> pred)
        {
            if (pred == null)
                yield break;

            T res = Next<T>();

            while (pred(res))
            {
                yield return res;

                res = Next<T>();
            }
        }

        public IEnumerable<T> NextSeq<T>(long n)
        {
            for (var i = 0; i < n; i++)
                yield return Next<T>();
        }

        public void Print(string format, params object[] args)
        {
            outputStream.Write(string.Format(CultureInfo.InvariantCulture, format, args));
        }

        public void PrintLine(string format, params object[] args)
        {
            Print(format, args);

            outputStream.WriteLine();
        }

        public void Print(bool o)
        {
            Print(o ? "yes" : "no");
        }

        public void PrintLine(bool o)
        {
            Print(o);

            outputStream.WriteLine();
        }

        public void Print<T>(T o)
        {
            outputStream.Write(Convert.ToString(o, CultureInfo.InvariantCulture));
        }

        public void PrintLine<T>(T o)
        {
            Print(o);

            outputStream.WriteLine();
        }

        public void Close()
        {
            inputStream.Close();
            outputStream.Close();
        }

        void IDisposable.Dispose()
        {
            Close();

#if  LOCAL_TEST
            Console.ReadLine();
#endif
        }
    }

    public static class ListExtensions
    {
        public static void Each<T>(this IEnumerable<T> self, Action<T> action)
        {
            foreach (var v in self)
                action(v);
        }

        public static IEnumerable<T> ToCycleEnumerable<T>(this IEnumerable<T> self)
        {
            if (self != null)
            {
                for (; ; )
                {
                    foreach (var x in self)
                        yield return x;
                }
            }
        }

        public static T CycleGet<T>(this IList<T> self, int index)
        {
            var c = self.Count;
            return self[(index % c + c) % c];
        }

        public static IList<T> Shuffle<T>(this IList<T> self)
        {
            var rnd = new Random(DateTime.Now.Millisecond);

            var n = self.Count;

            while (n > 1)
            {
                n--;
                var k = rnd.Next(n + 1);
                var value = self[k];
                self[k] = self[n];
                self[n] = value;
            }

            return self;
        }

        public static IList<IList<T>> UseForNew2D<T>(this T def, int fd, int sd)
        {
            var fdim = new T[fd][];

            for (int i = 0; i < fd; i++)
            {
                fdim[i] = new T[sd];
                Fill(fdim[i], def);
            }

            return fdim;
        }

        public static IList<T> Fill<T>(this IList<T> self, Func<T> fval)
        {
            for (var i = 0; i < self.Count; i++)
                self[i] = fval();

            return self;
        }

        public static IList<T> Fill<T>(this IList<T> self, T val)
        {
            return self.Fill(() => val);
        }

        public static long Hash<T>(this IList<T> self, Func<T, long> val = null)
        {
            return val != null ? self.Hash((t, current) => unchecked(current * 19L + val(t))) : self.Hash(HashOne);
        }

        public static long Hash<T>(this IList<T> self, Func<T, long, long> val)
        {
            return self.Aggregate(0L, (current, t) => unchecked(val(t, current)));
        }

        public static long HashOne<T>(this T self, long current)
        {
            return unchecked(current * 19L + (Equals(self, default(T)) ? 0 : self.GetHashCode()));
        }

        public static IList<T1> BuildSegTree<T1, T2>(this IList<T2> a, Func<T1, T1, T1> combine, Func<T2, T1> convert)
        {
            var t = new T1[a.Count << 2];

            a.BuildSegTree(t, 1, 0, a.Count - 1, combine, convert);

            return t;
        }

        private static void BuildSegTree<T1, T2>(this IList<T2> a, IList<T1> t, int v, int tl, int tr, Func<T1, T1, T1> combine, Func<T2, T1> convert)
        {
            if (tl == tr)
            {
                t[v] = convert(a[tl]);
            }
            else
            {
                int tm = (tl + tr) >> 1;

                BuildSegTree(a, t, v << 1, tl, tm, combine, convert);
                BuildSegTree(a, t, (v << 1) + 1, tm + 1, tr, combine, convert);

                t[v] = combine(t[v << 1], t[(v << 1) + 1]);
            }
        }
    }

    public static class P
    {
        public static P<T1, T2> Create<T1, T2>(T1 key, T2 val)
        {
            return new P<T1, T2>(key, val);
        }
    }

    public class P<T1, T2>
    {
        private class PComparer : IComparer<P<T1, T2>>
        {
            private readonly bool? byKey;

            public PComparer(bool? byKey)
            {
                this.byKey = byKey;
            }

            public int Compare(P<T1, T2> x, P<T1, T2> y)
            {
                x = x ?? new P<T1, T2>();
                y = y ?? new P<T1, T2>();

                if (byKey == true)
                    return Comparer<T1>.Default.Compare(x.Key, y.Key);
                else if (byKey == false)
                    return Comparer<T2>.Default.Compare(x.Value, y.Value);
                else
                {
                    var tr = Comparer<T1>.Default.Compare(x.Key, y.Key);

                    if (tr != 0)
                        tr = Comparer<T2>.Default.Compare(x.Value, y.Value);

                    return tr;
                }
            }
        }

        public P()
        {
        }

        public P(T1 key, T2 val)
        {
            this.Key = key;
            this.Value = val;
        }

        public T1 Key
        {
            get;
            set;
        }

        public T2 Value
        {
            get;
            set;
        }

        public P<T1, T2> Clone()
        {
            return new P<T1, T2>(Key, Value);
        }

        public static IComparer<P<T1, T2>> KeyComparer
        {
            get { return new PComparer(true); }
        }

        public static IComparer<P<T1, T2>> ValueComparer
        {
            get { return new PComparer(false); }
        }

        public static implicit operator T1(P<T1, T2> obj)
        {
            return obj.Key;
        }

        public static implicit operator T2(P<T1, T2> obj)
        {
            return obj.Value;
        }

        public P<T1, T2> SetKey(T1 key)
        {
            Key = key;
            return this;
        }

        public P<T1, T2> SetValue(T2 value)
        {
            Value = value;
            return this;
        }

        public override string ToString()
        {
            return string.Format("Key: {0}, Value: {1}", Key, Value);
        }

        public override bool Equals(object obj)
        {
            var co = obj as P<T1, T2>;

            return co != null && co.GetHashCode() == GetHashCode();
        }

        public override int GetHashCode()
        {
            int hash = 17;
            hash = hash * 31 + ((Equals(Key, default(T1))) ? 0 : Key.GetHashCode());
            hash = hash * 31 + ((Equals(Value, default(T1))) ? 0 : Value.GetHashCode());
            return hash;

        }
    }

    #endregion

    internal class Program
    {
        #region Program

        private readonly MyIo io;

        public Program(MyIo io)
        {
            this.io = io;
        }

        public static void Main(string[] args)
        {
            using (MyIo io = new MyIo())
            {
                new Program(io)
                    .Solve();
            }
        }

        #endregion
        public const long MOD = 1000000007;
        public const double EPS = 1e-14;

        private void Solve()
        {
            var n = io.NextInt();

            var keys = new[] {"chest", "biceps", "back"};
            var h = keys.ToDictionary(x => x, x => 0);

            for (int i = 0; i < n; i++)
            {
                h[keys[i%3]] += io.NextInt();
            }

            io.Print(h.OrderByDescending(x=>x.Value).FirstOrDefault().Key);

        }

    }

}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CodeForces
{
    class Program_R156_Div2_A
    {
        static void Main(string[] args)
        {
            int n = Convert.ToInt32(Console.ReadLine());
            string[] s = (Console.ReadLine().Split());
            int[] b = new int[Math.Max(n,3)];
            for (int i = 0; i < n; i++)
                b[i] = Convert.ToInt32(s[i]);

            for (int j = 3; j < n; j++)
                b[j % 3] += b[j];

            string ans = "back";
            if (b[0] > b[1] && b[0] > b[2])
                ans = "chest";
            else if (b[1] > b[0] && b[1] > b[2])
                ans = "biceps";

            Console.WriteLine(ans);
        }
    }
}

using System;
using System.Linq;

class Program
{
        static void Main(string[] args)
        {
            int n;
            string t;
            int biceps = 0;
            int chest = 0;
            int back = 0;

            t = Console.ReadLine();

            int.TryParse(t, out n);

            int[] a = new int[n];
            t = Console.ReadLine();

            string[] sa = t.Split(' ');

            for (int i = 0; i < n; i++)
            {
                int.TryParse(sa[i], out a[i]);
            }

            int buf = 1;

            for (int i = 0; i < n; i++)
            {
                switch (buf)
                {
                    case 1:
                        chest += a[i];
                        break;
                    case 2:
                        biceps += a[i];
                        break;
                    case 3:
                        back += a[i];
                        break;
                }
                buf++;
                if (buf == 4) buf = 1;
            }

            if (chest > biceps && chest > back) Console.WriteLine("chest");
            if (biceps > chest && biceps > back) Console.WriteLine("biceps");
            if (back > chest && back > biceps) Console.WriteLine("back");
        }
}

using System;

class Program
{
    static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        int[] arr = Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse);

        string result = "";
        int chestCount = 0;
        int bicepsCount = 0;
        int backCount = 0;
        for (int i = 0; i < n; i++)
        {
            int ex = i % 3;
            if (ex == 0)
                chestCount += arr[i];
            else if (ex == 1)
                bicepsCount += arr[i];
            else if (ex == 2)
                backCount += arr[i];
        }
        if (chestCount > bicepsCount && chestCount > backCount)
            Console.WriteLine("chest");
        else if (bicepsCount > chestCount && bicepsCount > backCount)
            Console.WriteLine("biceps");
        else if (backCount > chestCount && backCount > bicepsCount)
            Console.WriteLine("back");
    }
}

using System;

namespace vlad.a
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Convert.ToInt32(Console.ReadLine());
            string s = Console.ReadLine();
            string[] ss = s.Split(' ');
            int chest, biceps, back;
            chest = biceps = back = 0;
            for(int i = 0; i < n; i++)
            {
                switch(i % 3)
                {
                    case 0:
                        chest += Convert.ToInt32(ss[i]);
                        break;
                    case 1:
                        biceps += Convert.ToInt32(ss[i]);
                        break;
                    case 2:
                        back += Convert.ToInt32(ss[i]);
                        break;
                }
            }
            Console.WriteLine((chest > biceps) ? ((chest > back) ? "chest" : "back") : ((biceps > back) ? "biceps" : "back"));
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Globalization;
using System.Threading;
using System.Collections;
using System.IO;

namespace AcmSolution
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;
            //Console.SetIn(new StreamReader("gcd.in"));
           // Console.SetOut(new StreamWriter("gcd.out"));
            Do();
            //Console.Out.Close();
            Console.ReadLine();
        }

        private static void Do()
        {
            int n = GetInt();
            int[] a = GetInts();
            int sumChest = 0;
            int sumBiceps = 0;
            int sumBack = 0;
            string answer = "back";
            for (int i = 0; i < n; i += 3)
            {
                sumChest = sumChest + a[i];
            }
            for (int i = 1; i < n; i += 3)
            {
                sumBiceps = sumBiceps + a[i];
            }
            for (int i = 2; i < n; i += 3)
            {
                sumBack = sumBack + a[i];
            }
            if (sumChest > sumBiceps && sumChest > sumBack)
                answer = "chest";
            else if (sumBiceps > sumChest && sumBiceps > sumBack)
                answer = "biceps";

            Console.WriteLine(answer);
        }

     #region Utils
        private const double Epsilon = 0.00000001;

        private static string GetStr()
        {
            return Console.ReadLine();
        }

        private static string[] GetStrs()
        {
            return GetStr().Split(new[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
        }

        private static string[] GetStrs(int cnt)
        {
            var s = new string[cnt];
            for (var i = 0; i < cnt; ++i)
                s[i] = GetStr();
            return s;
        }

        private static int GetInt()
        {
            return int.Parse(GetStr());
        }

        private static void GetInts(out int a, out int b)
        {
            var q = GetInts();
            a = q[0];
            b = q[1];
        }

        private static void GetInts(out int a, out int b, out int c)
        {
            var q = GetInts();
            a = q[0];
            b = q[1];
            c = q[2];
        }

        private static int[] GetInts()
        {
            var s = GetStrs();
            var a = new int[s.Length];
            for (var i = 0; i < s.Length; ++i)
                a[i] = int.Parse(s[i]);
            return a;
        }

        private static long GetLong()
        {
            return long.Parse(GetStr());
        }

        private static IEnumerable<long> GetLongs()
        {
            return GetStrs().Select(long.Parse);
        }

        private static void WriteDouble<T>(T d)
        {
            Console.WriteLine(string.Format("{0:0.000000000}", d).Replace(',', '.'));
        }

        private static void WL<T>(T s)
        {
            Console.WriteLine(s);
        }

        private static void W<T>(T s)
        {
            Console.Write(s);
        }

        private static void Assert(bool b)
        {
            if (!b) throw new Exception();
        }

        private static void Swap<T>(ref T a, ref T b)
        {
            var temp = a;
            a = b;
            b = temp;
        }

        #endregion
    }
}

using System;
using System.Text;

namespace pr111
{
    class Program
    {
        public static void Main(string[] args)
        { int a,b,c,n;string s;
            n=Convert.ToInt16(Console.ReadLine());
            int[] arr;
            arr= new int[24];
            a = 0; b =0; c =0;
            string[] line=Console.ReadLine().Split();
            for (int i=0; i<line.Length; i++) {arr[i]=Convert.ToInt16(line[i]);}
            for (int i=1; i<24; i++) {if(i%3==1){a+=arr[i-1];} if(i%3==2){b+=arr[i-1];} if(i%3==0){c+=arr[i-1];}}
            if (a>=b&&a>=c) {s="chest";} else {if(b>c){s="biceps";} else {s="back";}}
            Console.WriteLine(Convert.ToString(s));
           // Console.ReadKey(true);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp10
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] l = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int[] y = new int[3];
            for (int i = 0; i < n; i++)
            {
                if ((i+1)%3==1)
                {
                    y[0]+=l[i];
                    continue;
                }
                else if ((i+1)%3==2)
                {
                    y[1]+=l[i];
                    continue;
                }
                else
                {
                    y[2]+=l[i];
                }
            }
            if (y.Max() == y[0])
            {
                Console.WriteLine("chest");
            }
            else if (y.Max() ==y[1])
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;

namespace CodeForces
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            var number = Int32.Parse(Console.ReadLine());
            var exercises = Console.ReadLine();
            var dataStr = exercises.Split(' ');
            List<int> data = dataStr.Select(int.Parse).ToList();
            Console.WriteLine(MostTrainedMuscle(number, data));
        }
        private static string MostTrainedMuscle(int number, List<int> data)
        {
            int chestExerciseCount = 0, bicepsExerciseCount = 0, backExcersiceCount = 0;

            for (var i = 0; i < number;)
            {
                int windows = number / 3;
                int remaining = number % 3;
                while (windows-- > 0)
                {
                    int chest = data[i];
                    int biceps = data[i + 1];
                    int back = data[i + 2];

                    chestExerciseCount += chest;
                    bicepsExerciseCount += biceps;
                    backExcersiceCount += back;

                    i += 3;
                }

                if (remaining != 0)
                {
                    i -= 1;
                    if (remaining == 1)
                    {
                        chestExerciseCount += data[i + 1];
                        break;
                    }

                    if (remaining == 2)
                    {
                        chestExerciseCount += data[i + 1];
                        bicepsExerciseCount += data[i + 2];
                        break;
                    }
                }
            }
            var result = Maxof3Numbers(chestExerciseCount, bicepsExerciseCount, backExcersiceCount);
            return result;
        }

        private static string Maxof3Numbers(int chestExerciseCount, int bicepsExerciseCount, int backExcersiceCount)
        {
            if (chestExerciseCount > bicepsExerciseCount && chestExerciseCount > backExcersiceCount)
                return "chest";
            if (bicepsExerciseCount > chestExerciseCount && bicepsExerciseCount > backExcersiceCount)
                return "biceps";
            if (backExcersiceCount > chestExerciseCount && backExcersiceCount > bicepsExerciseCount)
                return "back";
            return string.Empty;
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;

namespace CodeForces
{
    class Program
    {
        public static void Main(string[] args)
        {
            var number = Int32.Parse(Console.ReadLine());
            var exercises = Console.ReadLine();
            var dataStr = exercises.Split(' ');
            List<int> data = dataStr.Select(int.Parse).ToList();
            Console.WriteLine(MostTrainedMuscle(number, data));
        }

        private static string MostTrainedMuscle(int number, List<int> data)
        {
            int chestExerciseCount = 0, bicepsExerciseCount = 0, backExcersiceCount = 0;

            for (var i = 0; i < number;)
            {
                int windows = number / 3;
                int remaining = number % 3;
                while (windows-- > 0)
                {
                    int chest = data[i];
                    int biceps = data[i + 1];
                    int back = data[i + 2];

                    chestExerciseCount += chest;
                    bicepsExerciseCount += biceps;
                    backExcersiceCount += back;

                    i += 3;
                }

                if (remaining != 0)
                {
                    if (remaining == 1)
                    {
                        chestExerciseCount += data[i];
                        break;
                    }

                    if (remaining == 2)
                    {
                        chestExerciseCount += data[i];
                        bicepsExerciseCount += data[i + 1];
                        break;
                    }
                }
            }
            var result = Maxof3Numbers(chestExerciseCount, bicepsExerciseCount, backExcersiceCount);
            return result;
        }

        private static string Maxof3Numbers(int chestExerciseCount, int bicepsExerciseCount, int backExcersiceCount)
        {
            if (chestExerciseCount > bicepsExerciseCount && chestExerciseCount > backExcersiceCount)
                return "chest";
            if (bicepsExerciseCount > chestExerciseCount && bicepsExerciseCount > backExcersiceCount)
                return "biceps";
            if (backExcersiceCount > chestExerciseCount && backExcersiceCount > bicepsExerciseCount)
                return "back";
            return string.Empty;
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CF._255A
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int chest = 0, biceps = 0, back = 0;
            string[] a = Console.ReadLine().Split();
            for (int i = 0; i < n; i++)
                if (i % 3 == 0)
                    chest += int.Parse(a[i]);
                else if (i % 3 == 1)
                    biceps += int.Parse(a[i]);
                else
                    back += int.Parse(a[i]);
            if (chest >= biceps && chest >= back)
                Console.WriteLine("chest");
            else if (biceps >= chest && biceps >= back)
                Console.WriteLine("biceps");
            else
                Console.WriteLine("back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Linq;
using System.Runtime.Remoting.Messaging;
using System.Security;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Xml;

namespace codeforces
{
	class Program
	{
		public class User
		{
			public int c;

			public int r;
		}

		public class Comparer : IComparer<User>
		{
			public int Compare(User x, User y)
			{
				if (x.c < y.c)
					return -1;
				return 1;
			}
		}

		public static long getGcd(long a, long b)
		{
			if (b == 0)
				return a;
			return getGcd(b, a % b);
		}

		public static void WriteYESNO(bool x, string yes = "YES", string no = "NO")
		{
			if (x)
				Console.WriteLine(yes);
			else
			{
				Console.WriteLine(no);
			}
		}

		public static string GetString()
		{
			return Console.ReadLine();
		}

		public static List<int> getList()
		{
			var s = Console.ReadLine();
			return s.Split(' ').Select(int.Parse).ToList();
		}

		public static int Min(int x, int y)
		{
			return Math.Min(x, y);
		}

		public static int Max(int x, int y)
		{
			return Math.Max(x, y);
		}

		public static int Abs(int x)
		{
			return Math.Abs(x);
		}

		public static int getInt()
		{
			var s = Console.ReadLine();
			return int.Parse(s);
		}

		public static bool Equal(int x, int y, int x1, int y1)
		{
			return x == x1 && y == y1;
		}

		public class Vertex
		{
			public List<int> edges;

			public int ct;

			public Vertex()
			{
				ct = 0;
				edges = new List<int>();
				for (var i = 0; i < 26; ++i)
					edges.Add(0);
			}
		}

		private static void Main(string[] args)
		{
/*			var input = new StreamReader("input.txt");
			var output = new StreamWriter("output.txt");*/
			var n = getInt();
			var l = getList();
			var l1 = new List<int>();
			l1.Add(0);
			l1.Add(0);
			l1.Add(0);
			for (var i = 0; i < n; ++i)
				l1[i % 3] += l[i];
			var max = l1.Max();
			if (l1[0] == max)
				Console.WriteLine("chest");
			if (l1[1] == max)
				Console.WriteLine("biceps");
			if (l1[2] == max)
				Console.WriteLine("back");
			/*			input.Close();
			output.Close();*/
		}
	}
}

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApplication16
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            int n = Int32.Parse(Console.ReadLine());

            int spin = 0;
            int bicz = 0;
            int grud = 0;

            string fd = Console.ReadLine();

            int[] arrayiNT = new int[n];

            for (int i = 1; i < n + 1; i++)
            {
                arrayiNT[i - 1] = Int32.Parse(fd.Split(' ')[i - 1]);
                if (i%3 == 0)
                {
                    spin += arrayiNT[i - 1];
                }
                if (i%3 == 1)
                {
                    grud += arrayiNT[i - 1];
                }
                if (i%3 == 2)
                {
                    bicz += arrayiNT[i - 1];
                }
            }

            Dictionary<string, int> slovar = new Dictionary<string, int>()
            {
                {"back", spin},
                {"biceps", bicz},
                {"chest", grud}
            };
            List<int> upra = new List<int>();

            upra.Add(spin);
            upra.Add(grud);
            upra.Add(bicz);
            string dfgs = slovar.FirstOrDefault(el => el.Value == upra.Max()).Key;
            Console.WriteLine(dfgs);

        }
    }
}

using System;

namespace D2Problem1
{
    class Program
    {
        static void Main(string[] args)
        {
            int chest=0;
            int biceps = 0;
            int back = 0;
            int n = int.Parse(Console.ReadLine());
            int[] input = Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse);
            for (int i = 0; i < n; i += 3)
                chest += input[i];
            for (int i = 1; i < n; i += 3)
                biceps += input[i];
            for (int i = 2; i < n; i += 3)
                back += input[i];
            if(chest>biceps&&chest>back)
                Console.WriteLine("chest");
            else if(biceps>chest&&biceps>back)
                Console.WriteLine("biceps");
            else
                Console.WriteLine("back");

        }
    }
}

using System;
using System.Linq;

namespace _255A
{
    class Program
    {
        static void Main()
        {
            var n = int.Parse(Console.ReadLine());
            var array = Console.ReadLine().Split().Select(int.Parse).ToArray();
            var counter = 0;
            int chest = 0, biceps = 0, back = 0;
            for (int i = 0; i < n; i++)
            {
                switch (counter)
                {
                    case 0:
                        chest += array[i];
                        break;
                    case 1:
                        biceps += array[i];
                        break;
                    case 2:
                        back += array[i];
                        break;
                }
                counter++;
                if (counter > 2) counter = 0;
            }

            if (chest > biceps && chest > back) Console.WriteLine("chest");
            else if (biceps > chest && biceps > back) Console.WriteLine("biceps");
            else Console.WriteLine("back");
        }
    }
}

using System;
using System.Linq;
using System.Collections.Generic;
using System.Text;

namespace MakeCalendar
{
    class MainClass
    {

        static int ReadIntLine()
        {
            return int.Parse(Console.ReadLine());
        }

        static void ReadInt(ref int a)
        {
            a = ReadIntArrayLine()[0];
        }

        static void ReadInts(ref int a, ref int b)
        {
            var x = ReadIntArrayLine();
            a = x[0]; b = x[1];
        }

        static void ReadInts(ref int a, ref int b, ref int c)
        {
            var x = ReadIntArrayLine();
            a = x[0]; b = x[1]; c = x[2];
        }

        static void ReadInts(ref int a, ref int b, ref int c, ref int d)
        {
            var x = ReadIntArrayLine();
            a = x[0]; b = x[1]; c = x[2]; d = x[3];
        }

        static int[] ReadIntArrayLine()
        {
            char[] sep = { ' ' };
            return Console.ReadLine().Split(sep, StringSplitOptions.RemoveEmptyEntries).Select(x => int.Parse(x)).ToArray();
        }

        static void PrintLn(object obj)
        {
            Console.WriteLine(obj.ToString());
        }

        public static string Reverse(string s)
        {
            char[] charArray = s.ToCharArray();
            Array.Reverse(charArray);
            return new string(charArray);
        }

        public static void PrintLnCollection<T>(IEnumerable<T> col)
        {
            PrintLn(string.Join(" ",col));
        }

//----------------------------------------------------------------------------

        static void Main(string[] args)
        {
            int n = 0, c = 0;

            n = ReadIntLine() ;

            int[] a = ReadIntArrayLine();

            int chest = a.Where((x, xi) => xi % 3 == 0).Sum();
            int biceps = a.Where((y, yi) => yi % 3 == 1).Sum();
            int back = a.Where((z, zi) => zi % 3 == 2).Sum();

            if (chest == Math.Max(chest, Math.Max(biceps, back)))
                PrintLn("chest");
            if (biceps == Math.Max(chest, Math.Max(biceps, back)))
                PrintLn("biceps");
            if (back == Math.Max(chest, Math.Max(biceps, back)))
                PrintLn("back");

        }

    }
}

using System;

namespace ConsoleApplication32
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Int32.Parse(Console.ReadLine());
            int[] a = new int[n];
            string str = Console.ReadLine();
            string[] subString = str.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            int b = 0;
            int c = 0;
            int d = 0;
            for (int i = 0; i < n; i++)
            {
                a[i] = Convert.ToInt32(subString[i]);
            }
            for (int i = 0; i < n; i = i + 3)
            {
                b = b + a[i];
            }
            for (int i = 1; i < n; i = i + 3)
            {
                c = c + a[i];
            }
            for(int i = 2; i < n; i = i + 3)
            {
                d = d + a[i];
            }
            if (b > c && b > d)
            {
                Console.WriteLine("chest");
            }
            else if (c > d)
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace Codeforce {
    class Program {

        public class Muscle {
            public int Training = 0;
            public string Name = "";

            public override string ToString() {
                return Name;
            }

            public Muscle CompareTo(Muscle obj) {
                return this.Training > obj.Training ? this : (this.Training == obj.Training) ? this : obj;
            }
        }

        static void Main() {
            var n = Convert.ToInt32(Console.ReadLine());
            var tmpArr = Console.ReadLine().Split(' ');
            var list = new List<int>();
            for (int i = 0; i < n; i++) {
                list.Add(int.Parse(tmpArr[i]));
            }

            var chest = new Muscle() {
                Name = "chest"
            };
            var biceps = new Muscle() {
                Name = "biceps"
            };
            var back = new Muscle() {
                Name = "back"
            };

            for (int i = 0; i < n; i += 3) {
                chest.Training += list[i];
            }

            for (int i = 1; i < n; i += 3) {
                biceps.Training += list[i];
            }

            for (int i = 2; i < n; i += 3) {
                back.Training += list[i];
            }

            Console.WriteLine(chest.CompareTo(biceps.CompareTo(back)));
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _255A
{
    class Program
    {
        static void Main(string[] args)
        {
            int chest = 0, biceps = 0, back = 0;
            int n = int.Parse(Console.ReadLine());
            int[] a = Console.ReadLine().Split().Select(_ => int.Parse(_)).ToArray();
            for(int i = 0;i<n;i++)
            {
                switch((i+1)%3)
                {
                    case 1:chest += a[i];break;
                    case 2:biceps += a[i]; break;
                    case 0:back += a[i]; break;
                }
            }
            if (chest < biceps)
                Console.WriteLine(biceps > back ? "biceps" : "back");
            else
                Console.WriteLine(chest > back ? "chest" : "back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CFR156
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] ans = new int[3];
            int[] a = new int[n];
            string[] input = Console.ReadLine().Split(' ');
            for (int i = 0; i < n; i++)
                a[i] = int.Parse(input[i]);
            for (int i = 0,j=0; i < n; i++)
            {
                ans[j] += a[i];
                if (j == 2) j = -1;
                j++;
            }
            if (ans[0] > ans[1]&&ans[0]>ans[2])
                Console.WriteLine("chest");
            if (ans[1] > ans[0] && ans[1] > ans[2])
                Console.WriteLine("biceps");
            if (ans[2] > ans[0] && ans[2] > ans[1])
                Console.WriteLine("back");
            Console.ReadLine();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace ProjectContest
{
    class Test
    {
        static void Main()
        {
            int n = Convert.ToInt32(Console.ReadLine());
            int[] ex = new int[3];
            var a = Array.ConvertAll(Console.ReadLine().Split(), Convert.ToInt32);
            for(int i=0;i<n;i++)
            {
                ex[i % 3] += a[i];
            }
            if (ex.Max() == ex[0]) Console.WriteLine("chest");
            else if (ex.Max() == ex[1]) Console.WriteLine("biceps");
            else Console.WriteLine("back");
        }
    }
}

using System;

namespace codeforces{
  public class task{
    static void Main(){
      int n;
      int []tr={0,0,0};
      n=Convert.ToInt32(Console.ReadLine());
      int []training=new int[n];
      string[] str = Console.ReadLine().Split(new char[] { ' ', '\n', '\t' }, StringSplitOptions.RemoveEmptyEntries);
      for(int i=0;i<n;i++){
        training[i]=Convert.ToInt32(str[i]);
      }
      int k=1;
      for(int i=0;i<n;i++,k++){
        if(k==1){
          tr[0]+=training[i];
        }else{
          if(k==2){
            tr[1]+=training[i];
          }else if(k==3){
            tr[2]+=training[i];
            k=0;
          }
        }
      }
      if(tr[0]>tr[1]&&tr[0]>tr[2]){
        Console.WriteLine("chest");
      }else{
        if(tr[1]>tr[0]&&tr[1]>tr[2]){
          Console.WriteLine("biceps");
        }else{
          Console.WriteLine("back");
        }
      }
    }
  }
}

using System;
class Program
{
    static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        int[] args = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
        int biceps = 0, chest = 0, back = 0;
        for (int i = 0; i < args.Length; i++)
        {
            if (i % 3 == 0)
                chest += args[i];
            if ((i - 1) % 3 == 0)
                biceps += args[i];
            if ((i - 2) % 3 == 0)
                back += args[i];
        }
        if (chest > biceps && chest > back)
            Console.WriteLine(nameof(chest));
        if (biceps > chest && biceps > back)
            Console.WriteLine(nameof(biceps));
        if (back > chest && back > biceps)
            Console.WriteLine(nameof(back));
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace forcesGym
{
    class Program
    {
        static void Main(string[] args)
        {
            String xaxa = Console.ReadLine();
            int n = int.Parse(xaxa);

            int[] arr = new int[3];
            Array.Clear(arr,0,3);

            String babu = Console.ReadLine();
            String[] hadd=babu.Split(' ');
            for (int i = 0; i < n; i++)
            {
                int iRon = i % 3;

                int val = int.Parse(hadd[i]);

                arr[iRon] += val;

            }

            String res;

            if (arr[0] > arr[1] && arr[0] > arr[2])
                res = "chest";
            else if (arr[1] > arr[0] && arr[1] > arr[2])
                res = "biceps";
            else
                res = "back";

            Console.WriteLine(res);

        }
    }
}

using System;

namespace GregsWorkout
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());

            string [] input = Console.ReadLine().Split(new char[]{' '}, StringSplitOptions.None);

            int [] train = new int[3];
            for (int i=0; i<n; i++){
                train[i%3] += int.Parse(input[i]);
            }

            int max = int.MinValue;
            int maxIndex = 0;
            for (int i=0; i<3; i++){
                if (train[i] > max){
                    max = train[i];
                    maxIndex = i;
                }
            }

            switch(maxIndex){
                case 0:
                    Console.WriteLine("chest");
                    break;
                case 1:
                    Console.WriteLine("biceps");
                    break;
                case 2:
                    Console.WriteLine("back");
                    break;
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Codeforces
{
	class Program
	{
		static void Main(string[] args)
		{
			string input1 = Console.ReadLine();
			string input2 = Console.ReadLine();

			//var inputs1 = input1.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToArray();
			var inputs2 = input2.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse);

			var n = int.Parse(input1);
			var chest = inputs2.Where((item, index) => index % 3 == 0).Sum();
			var biceps = inputs2.Where((item, index) => index % 3 == 1).Sum();
			var back = inputs2.Where((item, index) => index % 3 == 2).Sum();

			var maxBicepsBack = Math.Max(biceps, back);
			if (chest > maxBicepsBack)
			{
				Console.WriteLine("chest");
			}
			else
			{
				var result = maxBicepsBack == biceps ? "biceps" : "back";
				Console.WriteLine(result);
			}
		}

		//private static long GCD(long a, long b)
		//{
		//	long max = Math.Max(a, b);
		//	long min = Math.Min(a, b);

		//	if (min == 0)
		//	{
		//		return max;
		//	}

		//	a = min;
		//	b = max % min;
		//	return GCD(a, b);
		//}

		//private static long LCM(long a, long b)
		//{
		//	return Math.Abs(a * b) / GCD(a, b);
		//}

		//private static int Length(short[] a)
		//{
		//	int firstItemIndex = 0;
		//	for (int i = 0; i < a.Length; i++)
		//	{
		//		if (a[i] == 0)
		//		{
		//			continue;
		//		}

		//		firstItemIndex = i;
		//		break;
		//	}

		//	return a.Length - firstItemIndex;
		//}

		//private static short[] Subtract(short[] a, short[] b)
		//{
		//	if (a.Length != b.Length)
		//	{
		//		throw new ArgumentException();
		//	}

		//	short[] result = new short[a.Length];
		//	Array.Copy(a, result, a.Length);
		//	for (int i = result.Length - 1; i >= 0; i--)
		//	{
		//		if (result[i] < b[i])
		//		{
		//			int j = i - 1;
		//			while (result[j] == 0)
		//			{
		//				result[j--] = 9;
		//			}

		//			result[j]--;
		//			result[i] += 10;
		//		}

		//		result[i] -= b[i];
		//	}

		//	return result;
		//}

		//private static short[] Multiply(short[] a, int b)
		//{
		//	short[] result = new short[a.Length];
		//	for (int i = a.Length - 1; i > 0; i--)
		//	{
		//		int temp = a[i] * b;
		//		result[i] = (short)(result[i] + temp % 10);
		//		result[i - 1] = (short)(result[i - 1] + temp / 10);
		//	}

		//	return result;
		//}

		//private static int Mod(short[] a, int b)
		//{
		//	int rest = 0, i = 0;
		//	while (i < a.Length)
		//	{
		//		int d = 10 * rest + a[i];
		//		while (d < b && i < a.Length - 1)
		//		{
		//			d = 10 * d + a[++i];
		//		}

		//		rest = d % b;
		//		i++;
		//	}

		//	return rest;
		//}

		//private static short[] Divide(short[] a, int b)
		//{
		//	short[] result = new short[a.Length];
		//	int rest = 0, i = 0;
		//	while (i < a.Length)
		//	{
		//		int d = 10 * rest + a[i];
		//		while (d < b && i < a.Length - 1)
		//		{
		//			d = 10 * d + a[++i];
		//		}

		//		result[i] = (short)(d / b);
		//		rest = d % b;
		//		i++;
		//	}

		//	return result;
		//}
	}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.IO;

namespace CF {

    class Program {

        static void Main(string[] args) {

#if DEBUG
            TextReader reader = new StreamReader("../../input.txt");
#else
			TextReader reader = Console.In;
#endif

            reader.ReadLine();
            var innn = reader.ReadLine().Split(' ').Select(int.Parse).ToArray();

            long[] trains = { 0, 0, 0 };

            for (int i = 0; i < innn.Length; i++) {
                trains[i % 3] += innn[i];
            }

            var m = trains.Max();
            if (trains[0] == m) {
                Console.WriteLine("chest");
            }
            if (trains[1] == m) {
                Console.WriteLine("biceps");
            }
            if (trains[2] == m) {
                Console.WriteLine("back");
            }

#if DEBUG
            Console.ReadKey();
#endif

        }

    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace prob6_Greg_s_Workout
{
    class Program
    {
        static void Main(string[] args)
        {
            var exerciseasNumber = Convert.ToInt32(Console.ReadLine());
            var exercises = Console.ReadLine();
            var exercisesSplit = exercises.Split(' ');
            int chest = 0;
            int biceps = 0;
            int back = 0;
            int newNumber = 0;

            for (var Number = 0; Number < exerciseasNumber; Number++)
            {
                if ((Number+1)%3 == 1)
                {
                    newNumber = Convert.ToInt32(exercisesSplit[Number]);
                    chest = chest + newNumber;
                }
                else if ((Number+1)%3 == 2)
                {
                    newNumber = Convert.ToInt32(exercisesSplit[Number]);
                    biceps = biceps + newNumber;
                }
                else if ((Number+1)%3 == 0)
                {
                    newNumber = Convert.ToInt32(exercisesSplit[Number]);
                    back = back + newNumber;
                }
            }

            if(chest > biceps && chest > back)
            {
                Console.WriteLine("chest");
            }
            if( biceps > chest && biceps > back)
            {
                Console.WriteLine("biceps");
            }
            if(back > chest && back > biceps)
            {
                Console.WriteLine("back");
            }
        }
        }
    }

/*

 */
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Diagnostics;

public class Solver
{
    public void Solve()
    {
        int n = ReadInt();
        int[] A = ReadIntArray();
        int chest = 0;
        int biceps = 0;
        int back = 0;
        for (int i = 0; i < n; i++) {
            if (i % 3 == 0)
                chest += A[i];
            else if (i % 3 == 1)
                biceps += A[i];
            else
                back += A[i];
        }
        if (chest > Math.Max(biceps, back))
            Write("chest");
        else if (biceps > Math.Max(chest, back))
            Write("biceps");
        else
            Write("back");

    }

    #region Main

    protected static TextReader reader;
    protected static TextWriter writer;
    static void Main()
    {
        Debug.Listeners.Clear();
        Debug.Listeners.Add(new ConsoleTraceListener());
        Trace.Listeners.Clear();
        Trace.Listeners.Add(new ConsoleTraceListener());

        reader = new StreamReader(Console.OpenStandardInput());
        writer = new StreamWriter(Console.OpenStandardOutput());
        new Solver().Solve();
        reader.Close();
        writer.Close();
    }

    #endregion

    #region Read / Write
    private static Queue<string> currentLineTokens = new Queue<string>();
    private static string[] ReadAndSplitLine() { return reader.ReadLine().Split(new[] { ' ', '\t', }, StringSplitOptions.RemoveEmptyEntries); }
    public static string ReadToken() { while (currentLineTokens.Count == 0)currentLineTokens = new Queue<string>(ReadAndSplitLine()); return currentLineTokens.Dequeue(); }
    public static int ReadInt() { return int.Parse(ReadToken()); }
    public static long ReadLong() { return long.Parse(ReadToken()); }
    public static double ReadDouble() { return double.Parse(ReadToken(), CultureInfo.InvariantCulture); }
    public static int[] ReadIntArray() { return ReadAndSplitLine().Select(int.Parse).ToArray(); }
    public static long[] ReadLongArray() { return ReadAndSplitLine().Select(long.Parse).ToArray(); }

    public static int[][] ReadIntMatrix(int numberOfRows) { int[][] matrix = new int[numberOfRows][]; for (int i = 0; i < numberOfRows; i++)matrix[i] = ReadIntArray(); return matrix; }
    public static int[][] ReadAndTransposeIntMatrix(int numberOfRows)
    {
        int[][] matrix = ReadIntMatrix(numberOfRows); int[][] ret = new int[matrix[0].Length][];
        for (int i = 0; i < ret.Length; i++) { ret[i] = new int[numberOfRows]; for (int j = 0; j < numberOfRows; j++)ret[i][j] = matrix[j][i]; } return ret;
    }
    public static string[] ReadLines(int quantity) { string[] lines = new string[quantity]; for (int i = 0; i < quantity; i++)lines[i] = reader.ReadLine().Trim(); return lines; }
    public static void WriteArray<T>(IEnumerable<T> array) { writer.WriteLine(string.Join(" ", array)); }
    public static void Write(params object[] array) { WriteArray(array); }
    public static void WriteLines<T>(IEnumerable<T> array) { foreach (var a in array)writer.WriteLine(a); }
    private class SDictionary<TKey, TValue> : Dictionary<TKey, TValue>
    {
        public new TValue this[TKey key]
        {
            get { return ContainsKey(key) ? base[key] : default(TValue); }
            set { base[key] = value; }
        }
    }
    private static T[] Init<T>(int size) where T : new() { var ret = new T[size]; for (int i = 0; i < size; i++)ret[i] = new T(); return ret; }
    #endregion
}

using System;
class CFR156D2A
{
	static void Main()
	{
		int chestCount = 0;
		int bicepsCount = 0;
		int backCount = 0;
		int n = int.Parse(Console.ReadLine());
		string[] data = Console.ReadLine().Split(' ');
		int checkIndex = 0;
		for (int i = 0; i < n; i++)
		{
			if (checkIndex == 0)
			{
				chestCount += int.Parse(data[i]);
				checkIndex++;
			}
			else if (checkIndex == 1)
			{
				bicepsCount += int.Parse(data[i]);
				checkIndex++;
			}
			else
			{
				backCount += int.Parse(data[i]);
				checkIndex = 0;
			}
		}
		if ((chestCount > bicepsCount) && (chestCount > backCount))
		{
			Console.WriteLine("chest");
		}
		else if ((bicepsCount > chestCount) && (bicepsCount > backCount))
		{
			Console.WriteLine("biceps");
		}
		else
		{
			Console.WriteLine("back");
		}
	}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;

class ans:IComparable<ans>
{
    public int a;
    public string name;
    public ans(int a, string s)
    {
        this.a = a;
        name = s;
    }
    public int CompareTo(ans a)
    {
        return this.a.CompareTo(a.a);
    }

}
class PairVariable:IComparable<PairVariable>
{
    public int a, b;
    public PairVariable()
    {
        a = b = 0;
    }
    public PairVariable(string s)
    {
        string[] q = s.Split();
        a = int.Parse(q[0]);
        b = int.Parse(q[1]);
    }
    public PairVariable(int a, int b)
    {
        this.a = a;
        this.b = b;
    }
    public int CompareTo(PairVariable pv)
    {
        if (this.a > pv.a)
        {
            return 1;
        }
        else if (this.a < pv.a)
        {
            return -1;
        }
        else
        {
            if (this.b >= pv.b)
            {
                return 1;
            }
            else
            {
                return -1;
            }
        }
    }

}
namespace ConsoleApplication252
{

    class Program
    {

        static bool P(int n)
        {
            for (int i = 2; i <= Math.Sqrt(n); i++)
            {
                if (n % i == 0)
                {
                    return false;
                }
            }
            return true;
        }

        static void Main()
        {
            int n = int.Parse(Console.ReadLine());
            string[] ss = Console.ReadLine().Split();
            int[] m = new int[n + 1];
            for (int i = 1; i < n + 1; i++)
            {
                m[i] = int.Parse(ss[i-1]);
            }
            int chest = 0;
            int biceps = 0;
            int back = 0;
            for (int i = 1; i < m.Length; i++)
            {
                if (i % 3 == 0)
                {
                    back += m[i];
                }
                else if (i % 3 == 1)
                {
                    chest += m[i];
                }
                else
                {
                    biceps += m[i];
                }

            }
            ans[] an = new ans[3];
            an[0] = new ans(chest, "chest");
            an[1] = new ans(biceps, "biceps");
            an[2] = new ans(back, "back");
            Array.Sort(an);
            Console.WriteLine(an[2].name);

        }
    }
}

using System;
class Solution
{
    public static void Main(string[] args)
    {
        int n = Convert.ToInt32(Console.ReadLine());
        string[] inputs = Console.ReadLine().Split(' ');
        int[] array = Array.ConvertAll(inputs, Int32.Parse);
        int k = 0, chest = 0, biseps = 0, back = 0;
        for (int i = 0; i < n; i++)
        {
            k++;
            if (k == 1) chest = chest + array[i];
            if (k == 2) biseps = biseps + array[i];
            if (k == 3) { back = back + array[i]; k = 0; }
        }
        if (chest > biseps && chest > back) Console.WriteLine("chest");
        if (biseps > chest && biseps > back) Console.WriteLine("biceps");
        if (back > chest && back > biseps) Console.WriteLine("back");
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CF_GregWorkout
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] a = Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse);
            Dictionary<string, int> dict = new Dictionary<string, int>();
            dict.Add("chest", 0);
            dict.Add("biceps", 0);
            dict.Add("back", 0);
            for(int i=0;i<n;i++)
            {
                if(i % 3 == 0)
                {
                    dict["chest"] = dict["chest"] + a[i];
                }
                else if (i % 3 == 1)
                {
                    dict["biceps"] = dict["biceps"] + a[i];
                }
                else if (i % 3 == 2)
                {
                    dict["back"] = dict["back"] + a[i];
                }
            }
            int max = dict.Values.Max();
            Console.WriteLine(dict.Single(d => d.Value == max).Key);
        }
    }
}

using System;
  class Program
    {
        static void Main(string[] args)
        {
            string[] input = Console.In.ReadToEnd().Split(new char[] { ' ', '\t', '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
            int[] counters = new int[3];
            for(int i=1; i<input.Length; ++i)
              counters[i%3]+=int.Parse(input[i]);
            input = null;
            int maxInd = 0;
            for(int i=1, curr = counters[0]; i<counters.Length; ++i)
             if (curr < counters[i]) { maxInd = i; curr = counters[i]; }
            counters = null;
            Console.WriteLine(maxInd == 0 ? "back" : maxInd == 1 ? "chest" : "biceps");
        }
    }

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Globalization;

namespace ConsoleApplication25
{
    class Program
    {
        static void Main(string[] args)
        {
            var init = int.Parse(Console.ReadLine());
            var nums = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();

            int chest = 0;
            int bicepc = 0;
            int back = 0;

            for (int i = 0; i < init; i++)
            {
                if (i % 3 == 0)
                {
                    chest += nums[i];
                }
                else if (i % 3 == 1)
                {
                    bicepc += nums[i];
                }
                else
                {
                    back += nums[i];
                }
            }

           if (chest > bicepc && chest > back)
           {
               Console.WriteLine("chest");
           }
           else if (bicepc > chest && bicepc > back)
           {
               Console.WriteLine("biceps");
           }
           else
           {
               Console.WriteLine("back");
           }
                Console.ReadLine();
        }
    }
}

using System;
using System.Linq;

class A255 {
    static string[] Name = {"chest", "biceps", "back"};

    public static void Main() {
        var n = int.Parse(Console.ReadLine());
        var a = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
        var b = new int[3];
        int k = 0;
        for (int i = 0; i < n; ++i) {
            b[k] += a[i];
            k = k == 2 ? 0 : k + 1;
        }
        Console.WriteLine(Name[Array.IndexOf(b, b.Max())]);
    }
}

using System;
using System.Linq;

namespace AcmSolution
{
    public class Program
    {
        public static void Main(string[] args)
        {
            Console.ReadLine();
            var s = Console.ReadLine().Split(' ');

            var a = new int[3];
            for (int i = 0; i < s.Length; ++i)
                a[i % 3] += int.Parse(s[i]);

            var max = a.Max();

            Console.WriteLine(a[0] == max ? "chest" : a[1] == max ? "biceps" : "back");
            Console.ReadLine();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CSharp_Contests
{
    public class Program
    {
        public static void Main() {
            int n = int.Parse(Console.ReadLine());
            int[] a = Console.ReadLine().Split(new char[1] { ' ' }).Select(b => int.Parse(b)).ToArray();
            int c = 0, bi = 0, ba = 0;
            n = n - ( n % 3 );
            for (int i = 0; i < n; i += 3)
            {
                c += a[i];
                bi += a[i + 1];
                ba += a[i + 2];
            }
            if (a.Length - n > 0)
                c += a[n];
            if (a.Length - n > 1)
                bi += a[n + 1];
            if (a.Length - n > 2)
                c += a[n + 2];

            if (c > bi && c > ba)
                Console.WriteLine("chest");
            else if (bi > c && bi > ba)
                Console.WriteLine("biceps");
            else if (ba > c && ba > bi)
                Console.WriteLine("back");
#if DEBUG
            Console.ReadLine();
#endif
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;
using System.IO;
using System.Numerics;
using System.Globalization;
using System.Threading;

namespace probleme {
    class Program {
        static void Main(string[] args) {
            //Console.SetIn(new StreamReader("file.txt"));
            int n = int.Parse(Console.ReadLine());
            int[] a = Array.ConvertAll(Console.ReadLine().Split(' '), tz => int.Parse(tz));
            int na = 0, nb = 0, nc = 0;
            for (int i = 0; i < n; i++) {
                if (i % 3 == 0)
                    na += a[i];
                else if (i % 3 == 1)
                    nb += a[i];
                else
                    nc += a[i];
            }
            if (na > nb && na > nc)
                Console.WriteLine("chest");
            else if (nb > na && nb > nc)
                Console.WriteLine("biceps");
            else
                Console.WriteLine("back");
            //Console.ReadKey();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            string[] c = Console.ReadLine().Split(' ');
            int iter = 0;
            int[] mass;
            mass = new int[3];
            for (int i = 0; i < n; i++)
            {
                int k = int.Parse(c[i]);
                mass[i % 3]+=k;
            }
            if (mass[0] > mass[1] && mass[0] > mass[2])
                Console.Write("chest");
            if (mass[1] > mass[0] && mass[1] > mass[2])
                Console.Write("biceps");
            if (mass[2] > mass[1] && mass[2] > mass[0])
                Console.Write("back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace A.Greg_s_Workout
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            string[] s = Console.ReadLine().Split();
            int[] arr = new int[n];
            for(int i=0 ;i<n;i++)
            {
                arr[i] = int.Parse(s[i]);
            }
            int chestsum = 0;
            int bicepssum = 0;
            int backsum = 0;
            for(int i=0;i<n;i+=3)
            {
                chestsum += arr[i];
            }
            for (int i = 1; i < n; i += 3)
            {
                bicepssum += arr[i];
            }
            for (int i = 2; i < n; i += 3)
            {
                backsum += arr[i];
            }
            if(chestsum>bicepssum&&bicepssum>backsum)
            {
                Console.WriteLine("chest");
            }
            else if(chestsum>backsum&&backsum>bicepssum)
            {
                Console.WriteLine("chest");
            }
            else if (chestsum > backsum && backsum == bicepssum)
            {
                Console.WriteLine("chest");
            }
            else if (bicepssum > backsum && backsum > chestsum)
            {
                Console.WriteLine("biceps");
            }
            else if (bicepssum > chestsum && chestsum > backsum)
            {
                Console.WriteLine("biceps");
            }
            else if (bicepssum > chestsum && chestsum == backsum)
            {
                Console.WriteLine("biceps");
            }
            else if (backsum > chestsum && chestsum > bicepssum)
            {
                Console.WriteLine("back");
            }
            else if (backsum > bicepssum && bicepssum > chestsum)
            {
                Console.WriteLine("back");
            }
            else if (backsum > bicepssum && bicepssum == chestsum)
            {
                Console.WriteLine("back");
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Tar
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Util.getNum();
            int[] array = Util.getArray();

            int a =0;
            int b =0;
            int c = 0;
            for (int i = 0; i < array.Length;i++ )
            {
                if(i%3==0){
                    a += array[i];
                }

                if (i % 3 == 1)
                {
                    b += array[i];
                }

                if (i % 3 == 2)
                {
                    c += array[i];
                }
            }

            if(a>b && a>c){
                Console.WriteLine("chest");
            }

            if (b > a && b > c)
            {
                Console.WriteLine("biceps");
            }

            if (c > a && c > b)
            {
                Console.WriteLine("back");
            }
        }

        public static int exper(decimal p1, decimal p2){
            int res = 0;
            while(res == 0){

                Random random = new Random();
                if ((decimal)random.NextDouble() > p1)
                {
                    res = 1;
                }

                if ((decimal)random.NextDouble() > p2)
                {
                    res = -1;
                }
            }

            return res;
        }
    }

    class Util
    {
        public static int getNum()
        {
            return int.Parse(Console.ReadLine());
        }

        public static int[] getArray()
        {
            string[] str = Console.ReadLine().Split(' ');
            int[] array = new int[str.Length];

            for (int i = 0; i < array.Length; i++)
            {
                try
                {
                    array[i] = int.Parse(str[i]);
                }
                catch (Exception e)
                {
                    //Console.WriteLine(str[i]+"/");
                }
            }

            return array;
        }
    }
}

using System;
using System.IO;
using System.Linq;

class Program
{
    static char[] SPACE = new[] { ' ' };

    static void Main(string[] args)
    {
#if DEBUG
        using (var input = new StreamReader("input.txt"))
        using (var output = new StreamWriter("output.txt"))
        {
            Console.SetIn(input);
            Console.SetOut(output);

            int n = 0;
            do
            {
                Console.WriteLine();
                Console.WriteLine("Sample {0}", ++n);
                Prog();
            } while (Console.ReadLine() == string.Empty);
        }
#else
            Prog();
#endif
    }

    static int __ptr = 0;
    static string[] __input;
    static int NextInt()
    {
        return int.Parse(__input[__ptr++]);
    }
    static long NextLong()
    {
        return long.Parse(__input[__ptr++]);
    }
    static void ReadTokens(int n)
    {
        __ptr = 0;
        __input = Console.ReadLine().Split(SPACE, n);
    }

    //

    static void Prog()
    {
        ReadTokens(1);
        int n = NextInt();

        int[] r = new int[3];

        ReadTokens(n);
        for (int i = 0; i < n; i++)
            r[i % 3] += NextInt();

        int max = Math.Max(Math.Max(r[0], r[1]), r[2]);
        if (max == r[0]) Console.WriteLine("chest");
        else if (max == r[1]) Console.WriteLine("biceps");
        else if (max == r[2]) Console.WriteLine("back");
    }

}

using System;
using System.Collections.Generic;
using System.IO;

namespace prA {

    class Program {
#if ONLINE_JUDGE
        private static readonly StreamReader reader = new StreamReader(Console.OpenStandardInput(1024 * 10), System.Text.Encoding.ASCII, false, 1024 * 10);
        private static readonly StreamWriter writer = new StreamWriter(Console.OpenStandardOutput(1024 * 10), System.Text.Encoding.ASCII, 1024 * 10);
#else
        private static readonly StreamWriter writer = new StreamWriter("output");
        private static readonly StreamReader reader = new StreamReader("input");
#endif
        static void Main(string[] args) {
            string[] w = {"chest", "biceps", "back"};
            int n = Next();
            int[] q = new int[3];
            int p = 0;
            int maxi = 0;
            for(int i = 0; i < n; i++) {
                int a = Next();
                q[p] += a;
                if(q[p] > q[maxi])
                    maxi = p;
                ++p;
                p %= 3;
            }
            writer.WriteLine(w[maxi]);
            writer.Flush();
#if !ONLINE_JUDGE
            writer.Close();
#endif
        }
        private static int Next() {
            int c;
            int res = 0;
            do {
                c = reader.Read();
                if(c == -1)
                    return res;
            } while(c != '-' && (c < '0' || c > '9'));
            int sign = 1;
            if(c == '-') {
                sign = -1;
                c = reader.Read();
            }
            res = c - '0';
            while(true) {
                c = reader.Read();
                if(c < '0' || c > '9')
                    return res * sign;
                res *= 10;
                res += c - '0';
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication3
{
    class Program
    {
        static int i(string s)
        {
            return Convert.ToInt32(s);
        }
        static void Main(string[] args)
        {
            int n = i(Console.ReadLine());
            int[] counts = new int[3];
            string[] s = Console.ReadLine().Split(' ');
            int j = 0;
            foreach (string s1 in s)
            {
                int temp = i(s1);
                counts[(j % 3)] += temp;
                j++;
            }
            int argmax = 0;
            int max = -1;
            for (int k = 0; k < 3; k++)
            {
                if (max < counts[k])
                {
                    max = counts[k];
                    argmax = k;
                }
            }
            if(argmax == 0)
                Console.WriteLine("chest");
            else if(argmax == 1)
                Console.WriteLine("biceps");
            else
                Console.WriteLine("back");

        }
    }
}

using System;
using System.Globalization;
using System.IO;
using System.Linq;

namespace CF317
{
	internal class Program
	{
		private static void Main(string[] args)
		{
			var sr = new InputReader(Console.In);
			//var sr = new InputReader(new StreamReader("input.txt"));
			var task = new Task();
			using (var sw = Console.Out)
				//using (var sw = new StreamWriter("output.txt"))
			{
				task.Solve(sr, sw);
				//Console.ReadKey();
			}
		}
	}

	internal class Task
	{
		public void Solve(InputReader sr, TextWriter sw)
		{
			var n = sr.NextInt32();
			var array = sr.ReadArray(Int32.Parse);
			var firstCount = 0;
			var secondcount = 0;
			var thirdCount = 0;
			for (var i = 0; i < n; i++) {
				if (i % 3 == 0) {
					firstCount += array[i];
				}
				if (i % 3 == 1) {
					secondcount += array[i];
				}
				if (i % 3 == 2) {
					thirdCount += array[i];
				}
			}

			var max = Math.Max(firstCount, Math.Max(secondcount, thirdCount));
			if (max == firstCount) {
				sw.WriteLine("chest");
			}
			else {
				if (max == secondcount) {
					sw.WriteLine("biceps");
				}
				else {
					sw.WriteLine("back");
				}
			}
		}
	}
}

internal class InputReader : IDisposable
{
	private bool isDispose;
	private readonly TextReader sr;

	public InputReader(TextReader stream)
	{
		sr = stream;
	}

	public void Dispose()
	{
		Dispose(true);
		GC.SuppressFinalize(this);
	}

	public string NextString()
	{
		var result = sr.ReadLine();
		return result;
	}

	public int NextInt32()
	{
		return Int32.Parse(NextString());
	}

	public long NextInt64()
	{
		return Int64.Parse(NextString());
	}

	public string[] NextSplitStrings()
	{
		return NextString()
			.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
	}

	public T[] ReadArray<T>(Func<string, CultureInfo, T> func)
	{
		return NextSplitStrings()
			.Select(s => func(s, CultureInfo.InvariantCulture))
			.ToArray();
	}

	public T[] ReadArrayFromString<T>(Func<string, CultureInfo, T> func, string str)
	{
		return
			str.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)
				.Select(s => func(s, CultureInfo.InvariantCulture))
				.ToArray();
	}

	protected void Dispose(bool dispose)
	{
		if (!isDispose) {
			if (dispose)
				sr.Close();
			isDispose = true;
		}
	}

	~InputReader()
	{
		Dispose(false);
	}
}

using System;
using System.IO;
using System.Text;

namespace Greg_s_Workout
{
    internal class Program
    {
        private static readonly StreamReader reader = new StreamReader(Console.OpenStandardInput(1024*10), Encoding.ASCII, false, 1024*10);
        private static readonly StreamWriter writer = new StreamWriter(Console.OpenStandardOutput(1024*10), Encoding.ASCII, 1024*10);

        private static void Main(string[] args)
        {
            int n = Next();

            var nn = new int[3];
            for (int i = 0; i < n; i++)
            {
                nn[i%3] += Next();
            }

            if (nn[0] > nn[1] && nn[0] > nn[2])
                writer.WriteLine("chest");
            else if (nn[1] > nn[2] && nn[1] > nn[2])
                writer.WriteLine("biceps");
            else
            {
                writer.WriteLine("back");
            }

            writer.Flush();
        }

        private static int Next()
        {
            int c;
            int res = 0;
            do
            {
                c = reader.Read();
                if (c == -1)
                    return res;
            } while (c < '0' || c > '9');
            res = c - '0';
            while (true)
            {
                c = reader.Read();
                if (c < '0' || c > '9')
                    return res;
                res *= 10;
                res += c - '0';
            }
        }
    }
}

using System;

namespace ConsoleApplication1
{
    internal class Program
    {
        private static int n;
        private static string[] s;
        private static int[] a;
        private static int x = 0, y = 0, z = 0;

        private static void Main(string[] args)
        {
            n = int.Parse(Console.ReadLine());

            s = Console.ReadLine().Split(' ');

            var k = 1;

            for (int i = 0; i < n; i++)
            {
                switch (k)
                {
                    case 1 :
                        x += int.Parse(s[i]);
                        break;
                    case 2:
                        y += int.Parse(s[i]);
                        break;
                    case 3:
                        z += int.Parse(s[i]);
                        break;
                }

                if (k == 3)
                    k = 1;
                else
                    k++;
            }

            Console.WriteLine(x > y ? x > z ? "chest" : "back" : y > z ? "biceps" : "back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Threading.Tasks;

namespace codeforce8
{
    class Program
    {
        static string Type(int [] arr,int n)
        {
            int chest = 0;
            int biceps = 0;
            int back = 0;

            double ff = (double)n / 3;
            /*for (int i = 0; i < 2; i++)
            {
                if (arr.Length % 3 == 0)
                {
                    break;
                }
                else arr.Append(0);
            }*/
                for (int  i = 0;  i < (Math.Ceiling(ff))*3;  i+=3)
                {
                    chest += arr[i];
                    biceps += arr[i + 1];
                    back += arr[i + 2];
                }
            if (chest > back && chest > biceps)
            {
                return "chest";
            }
           else if (biceps > back && chest <biceps)
            {
                return "biceps";
            }
           else if (chest < back && back > biceps)
            {
                return "back";
            }
            return "0";
        }
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] arr = new int[25];
            string str = Console.ReadLine();
            string[] st = str.Split();
            for (int i = 0; i < n; i++)
            {
                arr[i] = int.Parse(st[i]);
            }
            Console.WriteLine(Type(arr,n));
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Threading.Tasks;

namespace codeforce8
{
    class Program
    {
        static string Type(int [] arr,int n)
        {
            int chest = 0;
            int biceps = 0;
            int back = 0;

            double ff = (double)n / 3;

                for (int  i = 0;  i < (Math.Ceiling(ff))*3;  i+=3)
                {
                    chest += arr[i];
                    biceps += arr[i + 1];
                    back += arr[i + 2];
                }
            if (chest > back && chest > biceps)
            {
                return "chest";
            }
            else if (biceps > back && chest < biceps)
            {
                return "biceps";
            }
            else return "back";
        }
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] arr = new int[25];
            string str = Console.ReadLine();
            string[] st = str.Split();
            for (int i = 0; i < n; i++)
            {
                arr[i] = int.Parse(st[i]);
            }
            Console.WriteLine(Type(arr,n));
            Console.ReadLine();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Threading.Tasks;

namespace codeforce8
{
    class Program
    {
        static string Type(int [] arr,int n)
        {
            int chest = 0;
            int biceps = 0;
            int back = 0;

            double ff = (double)n / 3;

                for (int  i = 0;  i < (Math.Ceiling(ff))*3;  i+=3)
                {
                    chest += arr[i];
                    biceps += arr[i + 1];
                    back += arr[i + 2];
                }
            if (chest > back && chest > biceps)
            {
                return "chest";
            }
           else if (biceps > back && chest <biceps)
            {
                return "biceps";
            }
           else if (chest < back && back > biceps)
            {
                return "back";
            }
            return "0";
        }
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] arr = new int[25];
            string str = Console.ReadLine();
            string[] st = str.Split();
            for (int i = 0; i < n; i++)
            {
                arr[i] = int.Parse(st[i]);
            }
            Console.WriteLine(Type(arr,n));
        }
    }
}

using System;
using System.Linq;

namespace codeforces
{
    class Program
    {
        static void Main(string[] args)
        {
            int count = int.Parse(Console.ReadLine());
            int[] s = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int chest = 0,biceps = 0, back = 0;
            for (int i = 1; i <= count; i++)
            {
                if (i % 3 == 1)
                    chest += s[i - 1];
                if (i % 3 == 2)
                    biceps += s[i - 1];
                if (i % 3 == 0)
                    back += s[i - 1];
            }

            Console.WriteLine(chest > biceps && chest > back ? "chest" : biceps > chest && biceps > back ? "biceps" : "back");

        }
    }
}

using System;
using System.Linq;

namespace egor
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] exercises = { 0, 0, 0 };
            char c;
            int count = int.Parse(Console.ReadLine());

            for (int i = 0; i < count; i++)
            {
                string tmp = "";
                while (char.IsDigit(c = (char)(Console.Read()))) tmp += c;
                exercises[i % 3] += Convert.ToInt32(tmp);
            }

            switch (exercises.ToList().IndexOf(exercises.Max()))
            {
                case 0:
                    Console.WriteLine("chest");
                    break;

                case 1:
                    Console.WriteLine("biceps");
                    break;

                case 2:
                    Console.WriteLine("back");
                    break;
            }
        }
    }
}

using System;
using System.Linq;
class Test{
    static void Main(){
        int n = int.Parse(Console.ReadLine());
        int [] a = new int [3];
        string [] line = Console.ReadLine().Split();
        int j = 0;
        for(int i = 0; i < n; i++){
            if(j == 3){
                j = 0;
            }
            a[j] += int.Parse(line[i]);
            j++;
        }
        switch(Array.IndexOf(a, a.Max())){
            case 0:
                Console.WriteLine("chest"); break;
            case 1:
                Console.WriteLine("biceps"); break;
            case 2:
                Console.WriteLine("back"); break;
            default: break;
        }
    }
}

using System;

public class Exercise
{
    static void Main(string[] agrs)
    {

        var input1 = Console.ReadLine();
        var input2 = Console.ReadLine().Split();

        var n = int.Parse(input1);

        int chest = 0;
        int biceps = 0;
        int back = 0;

        for (int i = 0; i < n; i++)
        {
            if ((i + 1) % 3 == 0)
                back += int.Parse(input2[i]);

            if ((i + 1) % 3 == 1)
                chest += int.Parse(input2[i]);

            if ((i + 1) % 3 == 2)
                biceps += int.Parse(input2[i]);

        }

        int max = chest;
        string result = "chest";

        if (biceps > max)
        {
            max = biceps;
            result = "biceps";
        }

        if (back > max)
        {
            result = "back";
        }

        Console.WriteLine(result);

    }
}

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace CodeForces
{
	internal class Template
	{
		private static readonly Scanner cin = new Scanner();

		private static void Main()
		{
			//Console.SetIn(new StreamReader(@"C:\CodeForces\input.txt"));
			new Template().Solve();
		}

		private void Solve()
		{
			var n = cin.NextInt();
			var chest = 0;
			var biceps = 0;
			var back = 0;
			for (var i = 0; i < n; i++)
			{
				var c = cin.NextInt();
				if (i % 3 == 0)
				{
					chest += c;
				}
				if (i % 3 == 1)
				{
					biceps += c;
				}
				if (i % 3 == 2)
				{
					back += c;
				}
			}
			if (chest > biceps && chest > back)
			{
				Console.WriteLine("chest");
			}
			else if (biceps > back)
			{
				Console.WriteLine("biceps");
			}
			else
			{
				Console.WriteLine("back");
			}
		}
	}

	internal class Scanner
	{
		private string[] s = new string[0];
		private int i;
		private readonly char[] cs = new[] { ' ' };

		public string Next()
		{
			if (i < s.Length) return s[i++];
			var line = Console.ReadLine() ?? string.Empty;
			s = line.Split(cs, StringSplitOptions.RemoveEmptyEntries);
			i = 1;
			return s.First();
		}

		public double NextDouble()
		{
			return double.Parse(Next());
		}

		public int NextInt()
		{
			return int.Parse(Next());
		}

		public long NextLong()
		{
			return long.Parse(Next());
		}
	}
}

using System;
using System.Linq;

namespace CSharp
{
    public class _255A
    {
        public static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());

            var type = Console
                .ReadLine()
                .Split()
                .Select((token, i) => new
                {
                    Count = int.Parse(token),
                    Type = i % 3
                })
                .GroupBy(e => e.Type, e => e.Count)
                .Select(g => new
                {
                    Type = g.Key,
                    Count = g.Sum()
                })
                .OrderByDescending(e => e.Count)
                .First()
                .Type;

            Console.WriteLine(type == 0 ? "chest" : type == 1 ? "biceps" : "back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace test1
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            string[] strs = Console.ReadLine().Split();
            int[] cnt = { 0, 0, 0 };
            for (int i = 0; i < n; i++)
            {
                cnt[i % 3] += int.Parse(strs[i]);
            }
            if(cnt[0]>cnt[1]&&cnt[0]>cnt[2])
                Console.WriteLine("chest");
            else if(cnt[1]>cnt[2])
                Console.WriteLine("biceps");
            else
                Console.WriteLine("back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Solution
{
    class Program
    {
        static void Main(string[] args)
        {
            var n = int.Parse(Console.ReadLine());
            var Nums = Console.ReadLine().Split().Select( x => int.Parse(x) ).ToList();
            var group = new string[] {"chest", "biceps", "back"};
            var train = new Dictionary<string, int>
            {
                {group[0], 0}, {group[1], 0}, {group[2], 0}
            };
            for (var i = 0; i < n; i++)
            {
                train[group[i%3]]+=Nums[i];
            }
            var max = train.Values.Max();
            Console.WriteLine(train.FirstOrDefault(x=>x.Value == max).Key);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;

namespace Codeforces
{
    internal static class Program
    {
        private const string TEST = "A1";

        private static void Solve()
        {
            Read();
            var a = ReadIntArray();
            var res = new int[3];
            var resStr = new [] {"chest", "biceps", "back"};
            for (int i = 0; i < a.Count; i++)
            {
                    res[i%3] += a[i];

            }
            WriteLine(resStr[res[0] == res.Max() ? 0 : res[1] == res.Max() ? 1 : 2]);
        }

        private static void Main()
        {
            if (Debugger.IsAttached)
            {
                Console.SetIn(new StreamReader(String.Format(@"..\..\..\..\Tests\{0}.in", TEST)));
            }

            Solve();

            if (Debugger.IsAttached)
            {
                Console.In.Close();
                Console.SetIn(new StreamReader(Console.OpenStandardInput()));
                Console.ReadLine();
            }
        }

        #region Reader

        private static string Read()
        {
            return Console.ReadLine();
        }

        private static void Read(out int n1, out int n2)
        {
            var input = ReadArray();
            n1 = int.Parse(input[0]);
            n2 = int.Parse(input[1]);
        }
        private static void Read(out int n1, out int n2, out int n3)
        {
            var input = ReadArray();
            n1 = int.Parse(input[0]);
            n2 = int.Parse(input[1]);
            n3 = int.Parse(input[2]);
        }
        private static void Read(out int n1, out int n2, out int n3, out int n4)
        {
            var input = ReadArray();
            n1 = int.Parse(input[0]);
            n2 = int.Parse(input[1]);
            n3 = int.Parse(input[2]);
            n4 = int.Parse(input[3]);
        }

        private static void Read<T>(out T a1, out T a2)
        {
            var input = ReadArray();
            a1 = (T)Convert.ChangeType(input[0], typeof(T));
            a2 = (T)Convert.ChangeType(input[1], typeof(T));
        }

        private static void Read<T>(out T a1, out T a2, out T a3)
        {
            var input = ReadArray();
            a1 = (T)Convert.ChangeType(input[0], typeof(T));
            a2 = (T)Convert.ChangeType(input[1], typeof(T));
            a3 = (T)Convert.ChangeType(input[2], typeof(T));
        }

        private static void Read<T>(out T a1, out T a2, out T a3, out T a4)
        {
            var input = ReadArray();
            a1 = (T)Convert.ChangeType(input[0], typeof(T));
            a2 = (T)Convert.ChangeType(input[1], typeof(T));
            a3 = (T)Convert.ChangeType(input[2], typeof(T));
            a4 = (T)Convert.ChangeType(input[3], typeof(T));
        }

        private static int ReadInt()
        {
            return Int32.Parse(Read());
        }

        private static long ReadLong()
        {
            return long.Parse(Read());
        }

        private static double ReadDouble()
        {
            return double.Parse(Read(), CultureInfo.InvariantCulture);
        }

        private static T Read<T>()
        {
            return (T)Convert.ChangeType(Read(), typeof(T));
        }

        private static string[] ReadArray()
        {
            var readLine = Console.ReadLine();
            if (readLine != null)
                return readLine.Split(' ');

            throw new ArgumentException();
        }

        private static List<int> ReadIntArray()
        {
            return ReadArray().Select(Int32.Parse).ToList();
        }

        private static List<long> ReadLongArray()
        {
            return ReadArray().Select(long.Parse).ToList();
        }

        private static List<double> ReadDoubleArray()
        {
            return ReadArray().Select(d => double.Parse(d, CultureInfo.InvariantCulture)).ToList();
        }

        private static List<T> ReadArray<T>()
        {
            return ReadArray().Select(x => (T) Convert.ChangeType(x, typeof (T))).ToList();
        }

        private static void WriteLine(int value)
        {
            Console.WriteLine(value);
        }

        private static void WriteLine(double value)
        {
            Console.WriteLine(value.ToString(CultureInfo.InvariantCulture));
        }

        private static void WriteLine(long value)
        {
            Console.WriteLine(value);
        }

        private static void WriteLine(double value, string stringFormat)
        {
            Console.WriteLine(value.ToString(stringFormat, CultureInfo.InvariantCulture));
        }

        private static void WriteLine<T>(T value)
        {
            Console.WriteLine(value);
        }

        private static void Write(int value)
        {
            Console.Write(value);
        }

        private static void Write(double value)
        {
            Console.Write(value.ToString(CultureInfo.InvariantCulture));
        }

        private static void Write(long value)
        {
            Console.Write(value);
        }

        private static void Write(double value, string stringFormat)
        {
            Console.Write(value.ToString(stringFormat, CultureInfo.InvariantCulture));
        }

        private static void Write<T>(T value)
        {
            Console.Write(value);
        }

        #endregion
    }
}

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace Codeforces154
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Convert.ToInt32(Console.ReadLine());
            string[] s = Console.ReadLine().Split(' ');
            int[] a = new int[3];

            int k=0;
            for (int i=0;i<n;i++)
            {
                a[k]+=Convert.ToInt32(s[i]);
                k++;
                if (k==3)
                    k=0;
            }

            if (a[0]>Math.Max(a[1],a[2]))
                Console.WriteLine("chest");
            else if (a[1]>Math.Max(a[0],a[2]))
                Console.WriteLine("biceps");
            else
                Console.WriteLine("back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace A
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int chest = 0, back = 0, bic = 0;
            string[] s = Console.ReadLine().Split();
            for (int i = 0; i < n; i++)
            {
                if ((i+1)%3==1)
                {
                    chest += int.Parse(s[i]);
                }
                if ((i+1)%3==2)
                {
                    bic += int.Parse(s[i]);
                }
                if ((i + 1) % 3 == 0)
                {
                    back += int.Parse(s[i]);
                }
            }
            if (back>chest&&back>bic)
            {
                Console.WriteLine("back");
            }
            if (chest>back&&chest>bic)
            {
                Console.WriteLine("chest");
            }
            if (bic>chest&&bic>back)
            {
                Console.WriteLine("biceps");
            }
        }
    }
}

using System;
using System.Linq;

namespace olymp
{
  internal class Program
  {
    private static readonly string[] Answers = new[] { "chest", "biceps", "back" };

    private static void Main()
    {
      Console.ReadLine();
      var ex = Console.ReadLine().Split().Select(int.Parse).ToArray();
      var count = new int[3];
      for (int i = 0; i < ex.Length; i++)
        count[i % 3] += ex[i];
      for (int i = 0; i < 3; i++)
        if (count[i] == count.Max())
          Console.Write(Answers[i]);
    }
  }
}

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        int n = Convert.ToInt32(Console.ReadLine());
        int[] arr = Array.ConvertAll(Console.ReadLine().Split(' '), item => Convert.ToInt32(item));
        int chests = 0, biceps = 0, back = 0;
        for(int i=0;i<3;i++)
        {
            for(int j=i;j<arr.Length;j+=3)
            {
                if (i == 0) chests += arr[j];
                else if (i == 1) biceps += arr[j];
                else if (i == 2) back += arr[j];
            }
        }
        if (chests > biceps && chests > back) Console.Write("chest");
        else if (biceps > chests && biceps > back) Console.Write("biceps");
        else Console.Write("back");
    }
}

using System;
using static System.Console;
using System.Windows;
using static System.Math;

namespace ConsoleApp6
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(ReadLine());
            string[] b = ReadLine().Split(' ');
            int[] a = new int[b.Length + 1];
            int back = 0, biceps = 0, chest = 0;
            for (int i = 1; i <= b.Length; i++)
            {
                a[i] = Convert.ToInt32(b[i - 1]);
            }
            for (int i = 1; i <= b.Length; i++)
            {
                if (i % 3 == 0) back += a[i];
                else if (i % 3 == 2) biceps += a[i];
                else if (i % 3 == 1) chest += a[i];
            }
            if (Max(Max(back, biceps), chest) == back) WriteLine("back");
            else if (Max(Max(back, biceps), chest) == biceps) WriteLine("biceps");
            else Write("chest");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace A.Greg_s_Workout
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] x = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int chest = 0;
            int biceps = 0;
            int back = 0;
            for(int i=0;i<n;i+=3)
            {
                chest += x[i];
            } for (int i = 1; i < n; i += 3)
            {
                biceps += x[i];
            }
            for (int i = 2; i < n; i += 3)
            {
                back += x[i];
            }
            List<int> li = new List<int>();
            li.Add(chest); li.Add(biceps); li.Add(back);
            li.Sort();
            if(li[2]==chest)
            {
                Console.WriteLine("chest");
            }
            else if (li[2] == back)
            {
                Console.WriteLine("back");
            }
            else if (li[2] == biceps)
            {
                Console.WriteLine("biceps");
            }
        }
    }
}

using System;

namespace CodeForce156B_1
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Int32.Parse(Console.ReadLine());
            string[] st = Console.ReadLine().Split(' ');
            int count = 0;
            int sum1 = 0;
            int sum2 = 0;
            int sum3 = 0;
            for (int i = 0; i < st.Length; i++)
            {
                switch (count)
                {
                    case 0:
                        sum1 += Int32.Parse(st[i]);
                        break;
                    case 1:
                        sum2 += Int32.Parse(st[i]);
                        break;
                    case 2:
                        sum3 += Int32.Parse(st[i]);
                        break;
                    default:
                        sum1 += Int32.Parse(st[i]);
                        count = 0;
                        break;
                }
                count++;
            }
            if (sum1>sum2 && sum1>sum3)
                Console.WriteLine("chest");
            else if (sum2 > sum1 && sum2 > sum3)
                Console.WriteLine("biceps");
            else
                Console.WriteLine("back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TASK_255A
{
    class Program
    {
        static void Main(string[] args)
        {
            int count = int.Parse(Console.ReadLine());
            int[] arr = Console.ReadLine().Split().Select(x => int.Parse(x)).ToArray();
            int[] res = new[] { 0, 0, 0 };
            for (int i = 0; i < count; i++)
                res[i % 3] += arr[i];
            if (res[0] == res.Max())
                Console.WriteLine("chest");
            else if (res[1] == res.Max())
                Console.WriteLine("biceps");
            else
                Console.WriteLine("back");
            Console.ReadLine();
        }
    }
}

using System;
class a
{
    static void Main()
    {
        Console.ReadLine();
        var a = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
        int b, c, d; b = c = d = 0;
        for (int i = 0; i < a.Length; i+=3) b+= a[i];
        for (int i = 1; i < a.Length; i+=3) c+= a[i];
        for (int i = 2; i < a.Length; i+=3) d+= a[i];
        Console.WriteLine(b > c ? b > d ? "chest" : "back" : c > d ? "biceps" : "back");
    }
}

using System;
using System.Collections;
using System.Collections.Generic;

	class MainClass
	{
	public static string  findmax(int chest,int biceps,int back)
	{
		int val = Math.Max (Math.Max (chest, biceps), back);
		if (val == chest)
			return "chest";
		if (val == biceps)
			return "biceps";
		if (val == back)
			return "back";
		else
			return "none";
	}

	public static void Main(string[] args)
	{
		int n = Convert.ToInt32 (Console.ReadLine ());
		string[] values = Console.ReadLine ().Split ();
		int[] val = new int[n];
		int check = 0;
		int chest = 0, back = 0, biceps = 0;
		for (int i = 0; i < n; i++) {
			val [i] = Convert.ToInt32 (values [i]);
			if (check == 0) {
				chest =chest + val [i];
			}
			if (check == 1) {
				biceps = biceps+  val [i];
			}
			if (check == 2) {
				back = back + val [i];
				check++;
			}
			check++;
			if (check > 3)
				check = 0;

		}

		Console.WriteLine (findmax (chest, biceps, back));

	}

}

using System;
using System.Linq;
using System.Collections.Generic;

namespace AlgoTasks
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] a = Console.ReadLine().Split().Select(s => int.Parse(s)).ToArray();
            int chest = 0, biceps = 0, back = 0;
            for (int i = 0; i < n; i++)
            {
                if (i % 3 == 0) chest += a[i];
                else if (i % 3 == 1) biceps += a[i];
                else if (i % 3 == 2) back += a[i];
            }

            if (chest > biceps && chest > back)
                Console.WriteLine("chest");
            else if (biceps > chest && biceps > back)
                Console.WriteLine("biceps");
            else if (back > chest && back > biceps)
                Console.WriteLine("back");

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace _158Csharp
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Convert.ToInt32(Console.ReadLine());
            string s = Console.ReadLine();
            string[] p = s.Split(new string[] { " " }, StringSplitOptions.None);
            int[] A = new int[n];
            for (int i = 0; i < n; i++)
            {
                A[i] = Convert.ToInt32(p[i]);
            }
            int chest = 0;
            int biceps = 0;
            int back = 0;
            for (int i = 0; i < n; i++)
            {
                if (i % 3 == 0)
                {
                    chest += A[i];
                }
                else if (i % 3 == 1)
                {
                    biceps += A[i];
                }
                else if (i % 3 == 2)
                {
                    back += A[i];
                }
            }
            if (chest > biceps && chest > back)
                Console.WriteLine("chest");
            if (biceps > chest && biceps > back)
                Console.WriteLine("biceps");
            if (back > chest && back > biceps)
                Console.WriteLine("back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Pr1
{
    class Program
    {
        static void Main()
        {
            int n=Convert.ToInt32(Console.ReadLine());
            var all= Array.ConvertAll(Console.ReadLine().Split(' '), Convert.ToInt32);
            int[] a=new int[3];
            int s=0;
            for(int i=1;i<=n;i++)
            {
                if((i+2)%3==0)
                    a[0]+=all[i-1];
                else if((i+1)%3==0)
                    a[1]+=all[i-1];
                else
                    a[2]+=all[i-1];
            }
            int max=a.Max();
            if(a[0]==max)
                Console.WriteLine("chest");
            else if(a[1]==max)
                 Console.WriteLine("biceps");
            else
                 Console.WriteLine("back");

        }
    }
}

using System;
using System.Linq;

class Program {
  static void Main() {
    Console.ReadLine();
    var a = Console.ReadLine().Split(' ').Select(int.Parse).Select((x, i) => new {x, Index = i % 3}).GroupBy(t => t.Index).OrderByDescending(g => g.Sum(g1 => g1.x)).First().Key;
    Console.Write((new [] {"chest", "biceps", "back"})[a]);
  }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
             Console.ReadLine();
            string[] y = Console.ReadLine().Split(' ');
            int[] a = new int[y.Length];
            for (int i = 0; i < a.Length; i++)
            {
                a[i] = int.Parse(y[i]);
            }
            int chest = 0;
            int biceps = 0;
            int back = 0;
            for (int i = 0; i < a.Length; i += 3)
            {
                if (i < a.Length)
                {
                    chest += a[i];
                }
            }
            for (int i = 1; i < a.Length; i += 3)
            {
                if (i < a.Length)
                {
                    biceps += a[i];
                }
            }
            for (int i = 2; i < a.Length; i += 3)
            {
                if (i < a.Length)
                {
                    back += a[i];
                }
            }
            if ((chest > back) && (chest > biceps))
            {
                Console.WriteLine("chest");

            }
            if ((back > biceps) && (back > chest))
            {
                Console.WriteLine("back");

            }
            if ((biceps > back) && (biceps > chest))
            {
                Console.WriteLine("biceps");

            }
                //Console.ReadKey();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CSharp_Contests
{
    public class Program
    {
        public static void Main() {
            int n = int.Parse(Console.ReadLine());
            int[] a = Console.ReadLine().Split(new char[1] { ' ' }).Select(b => int.Parse(b)).ToArray();
            int c = 0, bi = 0, ba = 0;
            n = n - ( n % 3 );
            for (int i = 0; i < n; i += 3)
            {
                c += a[i];
                bi += a[i + 1];
                ba += a[i + 2];
            }
            if (a.Length - n > 0)
                c += a[n];
            if (a.Length - n > 1)
                bi += a[n + 1];
            if (a.Length - n > 2)
                c += a[n + 2];

            if (c > bi && c > ba)
                Console.WriteLine("chest");
            else if (bi > c && bi > ba)
                Console.WriteLine("biceps");
            else if (ba > c && ba > bi)
                Console.WriteLine("back");
#if DEBUG
            Console.ReadLine();
#endif
//ssss
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace A.Greg_s_Workout
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int chest = 0, biceps = 0, back = 0;
            int[] arr = Console.ReadLine().Split().Select(int.Parse).ToArray();
            if (n > 3)
            {
                for (int i = 0; i < n; i += 3)
                {
                    chest += arr[i];
                }
                for (int i = 1; i < n; i += 3)
                {
                    biceps += arr[i];
                }
                for (int i = 2; i < n; i += 3)
                {
                    back += arr[i];
                }
            }
            else
            {
                if (n == 3)
                {
                    chest = arr[0];
                    biceps = arr[1];
                    back = arr[2];
                }
                if (n == 2)
                {
                    chest = arr[0];
                    biceps = arr[1];
                }
                else if (n == 1) { Console.WriteLine("chest"); return; };
            }
            string[] s = { "chest", "biceps", "back" };
            int[] final = { chest, biceps, back };
            Console.WriteLine(s[Array.IndexOf(final, final.Max())]);
        }
    }
}

using System.Text;
using System.Linq;
using System;
using System.Collections;

class Program
{
    static void Main()
    {
        int s1 = Convert.ToInt32(Console.ReadLine());
        string s2 = Console.ReadLine();
        int[] sum = new int[3];

        string[] povtor = s2.Split(' ');

        for (int i=0; i<=povtor.Length - 1; i++)
        {
            sum[i%3] += Convert.ToInt32(povtor[i]);
        }

        if (sum[0] > sum[1] && sum[0] > sum[2])
        Console.WriteLine("chest");
        if (sum[1] > sum[0] && sum[1] > sum[2])
        Console.WriteLine("biceps");
        if (sum[2] > sum[1] && sum[2] > sum[0])
        Console.WriteLine("back");
    }
}

using System;
using System.Text.RegularExpressions;
using System.Collections.Generic;

namespace temp
{
    class MainClass
    {
        private static Int32[] read_ints(int n) {
            string[] str = Console.ReadLine().Split(new char[]{' '});
            Int32[] ret = new Int32[n];
            for (Int32 i = 0; i < n; i++)
                ret[i] = Convert.ToInt32(str[i]);
            return ret;
        }

        private static Int32 read_int() {
            return Convert.ToInt32(Console.ReadLine());
        }

        private static Int64[] read_longs(int n) {
            string[] str = Console.ReadLine().Split(new char[]{' '});
            Int64[] ret = new Int64[n];
            for (Int64 i = 0; i < n; i++)
                ret[i] = Convert.ToInt64(str[i]);
            return ret;
        }

        private static Int64 read_long() {
            return Convert.ToInt64(Console.ReadLine());
        }

        private static string read_line() {
            return Console.ReadLine();
        }

        public static void Main (string[] args)
        {
            int n = read_int(), chest = 0, biceps = 0, back = 0, m = 0;
            int[] arr = read_ints(n);
            for (int i = 0; i < n; i++) {
                if (m == 0)
                    chest += arr[i];
                else if (m == 1)
                    biceps += arr[i];
                else
                    back += arr[i];
                if (++m > 2)
                    m = 0;
            }
            if (chest > biceps && chest > back)
                Console.WriteLine("chest");
            else if (biceps > chest && biceps > back)
                Console.WriteLine("biceps");
            else
                Console.WriteLine("back");
        }
    }
}

using System;

namespace Greg_s_Workout
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Convert.ToInt32(Console.ReadLine());
            string[] line = Console.ReadLine().Split(' ');
            int[] exercices = new int[n];
            for (int i = 0; i < n; i++)
            {
                exercices[i] = Convert.ToInt32(line[i]);
            }
            int chest = 0;
            for (int i = 0; i < n; i = i + 3)
            {
                chest += exercices[i];
            }
            int biceps = 0;
            for (int i = 1; i < n; i = i + 3)
            {
                biceps += exercices[i];
            }
            int back = 0;
            for (int i = 2; i < n; i = i + 3)
            {
                back += exercices[i];
            }
            if (chest > biceps && chest > back)
            {
                Console.WriteLine("chest");
            }
            if (biceps > back && biceps > chest)
            {
                Console.WriteLine("biceps");
            }
            if(back > chest && back > biceps)
            {
                Console.WriteLine("back");
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GregsWorkout
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Int32.Parse(Console.ReadLine()), count = 0, chest = 0, biceps = 0, back = 0;
            int[] a = Array.ConvertAll(Console.ReadLine().Split(' '), Int32.Parse);
            int[] total;
            string[] name;
            for (int i = 0; i < n; i++)
            {
                count += 1;
                if (count == 1)
                    chest += a[i];
                else if (count == 2)
                    biceps += a[i];
                else if (count == 3)
                    back += a[i];
                if (count == 3)
                    count = 0;
            }
            total = new int[] { chest, biceps, back };
            name = new String[] { "chest", "biceps", "back" };
            Array.Sort(total, name);
            Console.WriteLine(name[2]);
            Console.ReadLine();
        }
    }
}

using System;
namespace A
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            string[] str = Console.ReadLine().Split(' ');
            int chest = 0;
            int biceps = 0;
            int back = 0;
            int k = 0;
            for (int i = 0; i < n; i++)
            {
                if (k == 0)
                {
                    chest += int.Parse(str[i]);
                }
                else if (k == 1)
                {
                    biceps += int.Parse(str[i]);
                }
                else
                {
                    back += int.Parse(str[i]);
                }
                k++;
                if (k == 3)
                {
                    k = 0;
                }
            }
            if (chest>biceps && chest>back)
            {
                Console.Write("chest");
            }
            else if (biceps> back && biceps>chest)
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }
        }
    }
}

using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Globalization;

namespace Codeforces_156Div2
{
	class Program
	{

		public void Solve ()
		{
			int n = io.NextInt ();

			var sum = new int[3];

			for (int i = 0; i < n; ++i)
			{
				int a = io.NextInt ();
				sum[ i % 3 ] += a;
			}

			int best = 0;
			for (int i = 0; i < 3; ++i)
				if (sum[i] > sum[best])
					best = i;

			io.PrintLine (new String[]{"chest", "biceps", "back"}[best]);
		}

        #region Program

        private readonly MyIo io;

        public Program(MyIo io)
        {
            this.io = io;
        }

        public static void Main(string[] args)
        {
            using (MyIo io = new MyIo())
            {
                new Program(io).Solve();
            }
        }

        #endregion
    }

    #region MyIo

    internal class MyIo : IDisposable
    {
        private readonly TextReader reader;
        private readonly TextWriter writer;

        private string[] tokens;
        private int pointer;

		public MyIo ()
			: this(Console.In, Console.Out)
		{
		}

		public MyIo (TextReader reader, TextWriter writer)
		{
			this.reader = reader;
			this.writer = writer;
		}

        public string NextLine()
        {
            try
            {
                return reader.ReadLine();
            }
            catch (IOException)
            {
                return null;
            }
        }

        public string NextString()
        {
            try
            {
                while (tokens == null || pointer >= tokens.Length)
                {
                    tokens = NextLine().Split(new char[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
                    pointer = 0;
                }
                return tokens[pointer++];
            }
            catch (IOException)
            {
                return null;
            }
        }

        public int NextInt()
        {
			int result;
			int.TryParse(NextString(), out result);
            return result;
        }

        public long NextLong()
        {
			long result;
			long.TryParse(NextString(), out result);
            return result;
        }

		public double NextDouble()
        {
			double result;
			double.TryParse(NextString(), out result);
            return result;
        }

        public T Next<T>()
        {
            return (T)Convert.ChangeType(NextString(), typeof(T));
        }

        public IEnumerable<T> NextSeq<T>(int n)
        {
			for (int i = 0; i < n; i++)
				yield return Next<T>();
        }

        public void Print(string format, params object[] args)
        {
            writer.Write(string.Format(CultureInfo.InvariantCulture, format, args));
        }

        public void PrintLine(string format, params object[] args)
        {
            Print(format, args);
            writer.WriteLine();
        }

        public void Print<T>(T o)
        {
            writer.Write(o);
        }

        public void PrintLine<T>(T o)
        {
            writer.WriteLine(o);
        }

        public void Close()
        {
            reader.Close();
            writer.Close();
        }

        void IDisposable.Dispose()
        {
            Close();
        }
    }

    #endregion
}

using System;
using System.Collections.Generic;
using System.Linq;
class Program
{
    static void Main()
    {
        int chest = 0, biceps = 0, back = 0;
        int counter = 0;
        string number = Console.ReadLine ();
        int n = Int32.Parse (number);
        string str = Console.ReadLine ();
        List<int> mains = new List<int> ();
        List<string> helpList = str.Split (' ').ToList();
        for (int i = 0; i < helpList.Count; i++) {
            mains.Add(Int32.Parse(helpList[i]));
        }
        int helpCounter = 0;
        for (int i = 1; i <= mains.Count; i++) {
            helpCounter++;
            if (helpCounter == 1)
                chest += mains [i - 1];
            else if (helpCounter == 2)
                biceps += mains [i - 1];
            else if (helpCounter == 3) {
                back += mains [i - 1];
                helpCounter = 0;
            }
        }
        if (chest > back && chest > biceps)
            Console.WriteLine ("chest");
        if (back > chest && back > biceps)
            Console.WriteLine ("back");
        if (biceps > chest && biceps > back)
            Console.WriteLine ("biceps");
    }
}

using System;
using System.Linq;

namespace codeforces
{
    class Program
    {
        static void Main(string[] args)
        {
            int count = int.Parse(Console.ReadLine());
            int[] s = Console.ReadLine().Split().Select(int.Parse).ToArray();
            //int numbers = Console.ReadLine().Split().Count(x => x.Count(y => y == '4' || y == '7') <= s[1]);
            int chest=0, biceps=0, back=0;
            for (int i = 1; i <= count; i++)
            {
                if (i % 3 == 1)
                    chest += i * s[i-1];
                if (i % 3 == 2)
                    biceps += i * s[i-1];
                if (i % 3 == 0)
                    back += i * s[i-1];
            }

            Console.WriteLine(chest>biceps&&chest>back? "chest" : biceps>chest&&biceps>back? "biceps" : "back");

        }
    }
}

using System;
using static System.Console;
using System.Windows;
using static System.Math;

namespace ConsoleApp6
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(ReadLine());
            string[] b = ReadLine().Split(' ');
            int[] a = new int[b.Length + 1];
            int back = 0, biceps = 0, chest = 0;
            for (int i = 1; i <= b.Length; i++)
            {
                a[i] = Convert.ToInt32(b[i - 1]);
            }
            for (int i = 1; i <= b.Length; i++)
            {
                if (i % 3 == 0) back += a[i];
                else if (i % 2 == 0) biceps += a[i];
                else if (i % 2 == 1) chest += a[i];
            }
            if (Max(Max(back, biceps), chest) == back) WriteLine("back");
            else if (Max(Max(back, biceps), chest) == biceps) WriteLine("biceps");
            else Write("chest");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] y = Console.ReadLine().Split(' ');
            int[] a = new int[y.Length];
            for (int i = 0; i < a.Length; i++)
            {
                a[i] = int.Parse(y[i]);
            }
            int chest = 0;
            int biceps = 0;
            int back = 0;
            for (int i = 0; i < a.Length; i += 3)
            {
                if (i < a.Length)
                {
                    chest += a[i];
                }
            }
            for (int i = 1; i < a.Length; i += 3)
            {
                if (i < a.Length)
                {
                    biceps += a[i];
                }
            }
            for (int i = 2; i < a.Length; i += 3)
            {
                if (i < a.Length)
                {
                    back += a[i];
                }
            }
            if ((chest > back) && (chest > biceps))
            {
                Console.WriteLine("chest");

            }
            if ((back > biceps) && (back > chest))
            {
                Console.WriteLine("back");

            }
            if ((biceps > back) && (biceps > chest))
            {
                Console.WriteLine("biceps");

            }
                //Console.ReadKey();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace A.Greg_s_Workout
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int chest = 0, biceps = 0, back = 0;
            int[] arr = Console.ReadLine().Split().Select(int.Parse).ToArray();
            if (n > 3)
            {
                for (int i = 0; i < n; i += 3)
                {
                    chest += arr[i];
                }
                for (int i = 1; i < n; i += 3)
                {
                    biceps += arr[i];
                }
                for (int i = 2; i < n; i += 3)
                {
                    back += arr[i];
                }
            }
            else
            {
                if (n == 3)
                {
                    chest = arr[0];
                    biceps = arr[1];
                    back = arr[2];
                }
                if (n == 2)
                {
                    chest = arr[0];
                    biceps = arr[1];
                }
                else if (n == 1) Console.WriteLine("chest");
            }
            string[] s = { "chest", "biceps", "back" };
            int[] final = { chest, biceps, back };
            Console.WriteLine(s[Array.IndexOf(final, final.Max())]);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CodeForces
{
    class Program_R156_Div2_A
    {
        static void Main(string[] args)
        {
            int n = Convert.ToInt32(Console.ReadLine());
            string[] s = (Console.ReadLine().Split());
            int[] b = new int[Math.Max(n,3)];
            for (int i = 0; i < n; i++)
                b[i] = Convert.ToInt32(s[i]);

            for (int j = 3; j < n; j++)
                b[j % 3] += b[j];

            string ans = "back";
            if (b[0] > b[1] && b[1] > b[2])
                ans = "chest";
            else if (b[1] > b[0] && b[1] > b[2])
                ans = "biceps";

            Console.WriteLine(ans);
        }
    }
}

using System;
using System.Text;

namespace pr111
{
    class Program
    {
        public static void Main(string[] args)
        { int a,b,c,n;string s;
            n=Convert.ToInt16(Console.ReadLine());
            int[] arr;
            arr= new int[24];
            a = 0; b =0; c =0;
            string[] line=Console.ReadLine().Split();
            for (int i=0; i<line.Length; i++) {arr[i]=Convert.ToInt16(line[i]);}
            for (int i=0; i<n-1; i+=3) {a+=arr[i]; b+=arr[i+1]; c+=arr[i+2];}
            if (a>=b&&a>=c) {s="chest";} else {if(b>c){s="biceps";} else {s="back";}}
            Console.WriteLine(Convert.ToString(s));
            //Console.ReadKey(true);
        }
    }
}

using System;

namespace ConsoleApplication32
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Int32.Parse(Console.ReadLine());
            int[] a = new int[n];
            string str = Console.ReadLine();
            string[] subString = str.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            int b = 0;
            int c = 0;
            int d = 0;
            for (int i = 0; i < n; i++)
            {
                a[i] = Convert.ToInt32(subString[i]);
            }
            for (int i = 0; i < n; i = i + 3)
            {
                b = b + a[i];
            }
            for (int i = 1; i < n; i = i + 3)
            {
                c = c + a[i];
            }
            for(int i = 2; i < n; i = i + 3)
            {
                d = d + a[i];
            }
            if (b > c && b > d)
            {
                Console.WriteLine("biceps");
            }
            else if (c > d)
            {
                Console.WriteLine("back");
            }
            else
            {
                Console.WriteLine("chest");
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _255A
{
    class Program
    {
        static void Main(string[] args)
        {
            int chest = 0, biceps = 0, back = 0;
            int n = int.Parse(Console.ReadLine());
            int[] a = Console.ReadLine().Split().Select(_ => int.Parse(_)).ToArray();
            for(int i = 0;i<n;i++)
            {
                switch((i+1)%3)
                {
                    case 1:chest++;break;
                    case 2:biceps++;break;
                    case 0:back++;break;
                }
            }
            if (chest < biceps)
                Console.WriteLine(biceps > back ? "biceps" : "back");
            else
                Console.WriteLine(chest > back ? "chest" : "back");
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _255A
{
    class Program
    {
        static void Main(string[] args)
        {
            int chest = 0, biceps = 0, back = 0;
            int n = int.Parse(Console.ReadLine());
            int[] a = Console.ReadLine().Split().Select(_ => int.Parse(_)).ToArray();
            for(int i = 0;i<n;i++)
            {
                switch((i+1)%3)
                {
                    case 1:chest++;break;
                    case 2:biceps++;break;
                    case 3:back++;break;
                }
            }
            if (chest < biceps)
                Console.WriteLine(biceps > back ? "biceps" : "back");
            else
                Console.WriteLine(chest > back ? "chest" : "back");
        }
    }
}

using System;

namespace codeforces{
  public class task{
    static void Main(){
      int n;
      int []tr={0,0,0};
      n=Convert.ToInt32(Console.ReadLine());
      int []training=new int[n];
      string[] str = Console.ReadLine().Split(new char[] { ' ', '\n', '\t' }, StringSplitOptions.RemoveEmptyEntries);
      for(int i=0;i<n;i++){
        training[i]=Convert.ToInt32(str[i]);
      }
      for(int i=0,k=1;i<n;i++,k++){
        if(k==1){
          tr[0]+=training[i];
        }else{
          if(k==2){
            tr[1]+=training[i];
          }else if(k==3){
            tr[2]+=training[i];
            k=1;
          }
        }
      }
      if(tr[0]>tr[1]&&tr[0]>tr[2]){
        Console.WriteLine("chest");
      }else{
        if(tr[1]>tr[0]&&tr[1]>tr[2]){
          Console.WriteLine("biceps");
        }else{
          Console.WriteLine("back");
        }
      }
    }
  }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp10
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] l = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int[] y = new int[3];
            for (int i = 0; i < n; i++)
            {
                if ((i+1)%3==1)
                {
                    y[1]++;
                    continue;
                }
                else if ((i+1%3)==2)
                {
                    y[2]++;
                }
                else
                {
                    y[0]++;
                }
            }
            if (y.Max() == y[0])
            {
                Console.WriteLine("chest");
            }
            else if (y.Max() ==y[1])
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp10
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] l = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int u = 0;
            int y = 0;
            for (int i = 1; i < n; i++)
            {
                if (l[i]>l[i-1])
                {
                    u = l[i];
                    y = i;
                }
            }
            if ((y+1)%3==1)
            {
                Console.WriteLine("chest");
            }
             else if((y+1)%3==2)
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp10
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] l = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int[] y = new int[3];
            for (int i = 0; i < n; i++)
            {
                if ((i+1)%3==1)
                {
                    y[0]+=l[i];
                    continue;
                }
                else if ((i+1%3)==2)
                {
                    y[1]+=l[i];
                    continue;
                }
                else
                {
                    y[2]+=l[i];
                }
            }
            if (y.Max() == y[0])
            {
                Console.WriteLine("chest");
            }
            else if (y.Max() ==y[1])
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp10
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] l = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int[] y = new int[3];
            for (int i = 0; i < n; i++)
            {
                if ((i+1)%3==1)
                {
                    y[1]++;
                    continue;
                }
                else if ((i+1%3)==2)
                {
                    y[2]++;
                }
                else
                {
                    y[0]++;
                }
            }
            if (l.Max() == y[0])
            {
                Console.WriteLine("chest");
            }
            else if (l.Max() ==y[1])
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp10
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] l = Console.ReadLine().Split().Select(int.Parse).ToArray();
            int[] y = new int[3];
            for (int i = 0; i < n; i++)
            {
                if ((i+1)%3==1)
                {
                    y[1]++;
                    continue;
                }
                else if ((i+1%3)==2)
                {
                    y[2]++;
                }
                else
                {
                    y[0]++;
                }
            }
            if (l.Max() == l[0])
            {
                Console.WriteLine("chest");
            }
            else if (l.Max() ==l[1])
            {
                Console.WriteLine("biceps");
            }
            else
            {
                Console.WriteLine("back");
            }

        }
    }
}

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Globalization;

namespace ConsoleApplication25
{
    class Program
    {
        static void Main(string[] args)
        {
            var init = int.Parse(Console.ReadLine());
            var nums = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();

            int chest = 0;
            int bicepc = 0;
            int back = 0;

            for (int i = 1; i <= init; i++)
            {
                if (i % 3 == 0)
                {
                    back += nums[i-1];
                }
                else if (i % 3 != 0 && i % 2 == 0)
                {
                    bicepc += nums[i-1];
                }
                else
                {
                    chest += nums[i-1];
                }
            }

           if (chest > bicepc && chest > back)
           {
               Console.WriteLine("chest");
           }
           else if (bicepc > chest && bicepc > back)
           {
               Console.WriteLine("biceps");
           }
           else
           {
               Console.WriteLine("back");
           }
                Console.ReadLine();
        }
    }
}

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Globalization;

namespace ConsoleApplication25
{
    class Program
    {
        static void Main(string[] args)
        {
            var init = int.Parse(Console.ReadLine());
            var nums = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();

            int chest = 0;
            int bicepc = 0;
            int back = 0;

            for (int i = 0; i < init; i++)
            {
                if (nums[i] % 3 == 0)
                {
                    chest += nums[i];
                }
                else if (nums[i] % 3 != 0 && nums[i] % 2 == 0)
                {
                    bicepc += nums[i];
                }
                else
                {
                    back += nums[i];
                }
            }

           if (chest > bicepc && chest > back)
           {
               Console.WriteLine("chest");
           }
           else if (bicepc > chest && bicepc > back)
           {
               Console.WriteLine("biceps");
           }
           else
           {
               Console.WriteLine("back");
           }
                Console.ReadLine();
        }
    }
}

using System;
using System.Linq;

class Program {
  static void Main() {
    Console.ReadLine();
    var a = Console.ReadLine().Split(' ').Select(int.Parse).Select((x, i) => new {x, Index = i % 3}).GroupBy(t => t.Index).OrderByDescending(g => g.Count()).First().Key;
    Console.Write((new [] {"chest", "biceps", "back"})[a]);
  }
}

using System;
using System.Linq;

class Program {
  static void Main() {
    Console.ReadLine();
    var a = Console.ReadLine().Split(' ').Select(int.Parse).Select((i, x) => i % 3).GroupBy(t => t).OrderByDescending(g => g.Count()).First().Key;
    Console.Write((new [] {"chest", "biceps", "back"})[a]);
  }
}

using System;

namespace ConsoleApplication1
{
    internal class Program
    {
        private static int n;
        private static string[] s;
        private static int[] a;
        private static int x = 0, y = 0, z = 0;

        private static void Main(string[] args)
        {
            n = int.Parse(Console.ReadLine());

            s = Console.ReadLine().Split(' ');

            var k = 1;

            for (int i = 0; i < n; i++)
            {
                switch (k)
                {
                    case 1 :
                        x += int.Parse(s[i]);
                        break;
                    case 2:
                        y += int.Parse(s[i]);
                        break;
                    case 3:
                        z += int.Parse(s[i]);
                        break;
                }

                if (k == 3)
                    k = 0;
                else
                    k++;
            }

            Console.WriteLine(x > y ? x > z ? "chest" : "back" : y > z ? "biceps" : "back");
        }
    }
}

using System;
using System.Linq;
using System.Collections.Generic;

namespace tren
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine()), chest = 0, biceps = 0, back = 0;
            List<int> mass = Console.ReadLine().Split(' ').Select(int.Parse).ToList();
            chest = mass.Where(x => mass.IndexOf(x) % 3 == 0).Sum();
            for (int i = 0; i < n; i++)
            {
                if (i % 3 == 0) mass[i] = 0;
            }
            for (int i = 0; i < mass.Count(); i++)
            {
                if (mass[i] == 0) mass.Remove(mass[i]);
            }

            for (int i = 0; i < mass.Count(); i++)
            {
                if (i % 2 == 0) biceps += mass[i];
                else back += mass[i];
            }
            if (biceps > chest && biceps > back) Console.Write("biceps");
            if (chest  > biceps && chest > back) Console.Write("chest");
            if (back > chest && back > biceps) Console.Write("back");
        }
    }
}

using System;
using System.Linq;
class Program
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine());
        var a = Console.ReadLine().Split().Select(int.Parse).ToArray();
        var m = new int[3];
        for (int i = 0; i < n; i++)
        {
            m[i % 3]++;
        }
        Console.WriteLine("{0}", new string[] { "chest", "biceps", "back" }[Array.IndexOf(m, m.Max())]);
    }
}

using System;
using System.Linq;
class Program
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine());
        var a = Console.ReadLine().Split().Select(int.Parse).ToArray();
        var muscle = new int[3];
        for (int i = 0; i < n; i++)
        {
            muscle[i % 3]++;
        }
        Console.WriteLine(muscle[0] > muscle[1] ? "chest" : muscle[1] > muscle[2] ? "biceps" : "back");
    }
}