Problem:
Score : 200 points

Problem Statement

A string is called a KEYENCE string when it can be changed to keyence by removing its contiguous substring (possibly empty) only once.

Given a string S consisting of lowercase English letters, determine if S is a KEYENCE string.

Constraints

The length of S is between 7 and 100 (inclusive).

S consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If S is a KEYENCE string, print YES; otherwise, print NO.

Sample Input 1

keyofscience

Sample Output 1

YES

keyence is an abbreviation of key of science.

Sample Input 2

mpyszsbznf

Sample Output 2

NO

Sample Input 3

ashlfyha

Sample Output 3

NO

Sample Input 4

keyence

Sample Output 4

YES

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using static System.Console;
using static System.Math;

namespace atcoder
{
    class Program
    {
        static void Main(string[] args)
        {
            new Program().Solve(new ConsoleInput(In));
        }

        public long Min(params long[] a)
        {
            var min = a[0];
            for (int i = 1; i < a.Length; i++)
            {
                if (min > a[i]) min = a[i];
            }
            return min;
        }

        public long Max(params long[] a)
        {
            var max = a[0];
            for (int i = 1; i < a.Length; i++)
            {
                if (max < a[i]) max = a[i];
            }
            return max;
        }

        public void Solve(ConsoleInput input)
        {
            var s = input.Read.ToCharArray();
            var ks = "keyence".ToCharArray();

            for (var i = 0; i < s.Length; i++)
            {
                for (var j = 0; j < s.Length - i; j++)
                {
                    var ss = s.ToList();
                    ss.RemoveRange(i, j);
                    WriteLine(new string(ss.ToArray()));
                    if (ss.SequenceEqual(ks))
                    {
                        WriteLine("YES");
                        return;
                    }
                }
            }
            WriteLine("NO");

            //Solve(input);
        }

        private long Xxor(long x, long[] a)
        {
            long fx = 0;
            foreach (var ai in a)
            {
                fx += x ^ ai;
            }
            return fx;
        }
    }

    public class ConsoleInput
    {
        private readonly System.IO.TextReader _stream;
        private readonly char _separator = ' ';
        private Queue<string> inputStream;
        public ConsoleInput(System.IO.TextReader stream, char separator = ' ')
        {
            _separator = separator;
            _stream = stream;
            inputStream = new Queue<string>();
        }
        public string Read
        {
            get
            {
                if (inputStream.Count != 0) return inputStream.Dequeue();
                string[] tmp = _stream.ReadLine().Split(_separator);
                for (int i = 0; i < tmp.Length; ++i)
                    inputStream.Enqueue(tmp[i]);
                return inputStream.Dequeue();
            }
        }
        public string ReadLine { get { return _stream.ReadLine(); } }
        public int ReadInt { get { return int.Parse(Read); } }
        public long ReadLong { get { return long.Parse(Read); } }
        public double ReadDouble { get { return double.Parse(Read); } }
        public string[] ReadStrArray(long N) { var ret = new string[N]; for (long i = 0; i < N; ++i) ret[i] = Read; return ret; }
        public int[] ReadIntArray(long N) { var ret = new int[N]; for (long i = 0; i < N; ++i) ret[i] = ReadInt; return ret; }
        public long[] ReadLongArray(long N) { var ret = new long[N]; for (long i = 0; i < N; ++i) ret[i] = ReadLong; return ret; }
    }
}