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: Accepted)

using System;
using System.Linq;
using System.Collections.Generic;
using static System.Console;
using System.Text;
using System.IO;
using static System.Math;
namespace AtCoder
{
    class Program
    {
        static public long[] Sarray() { return ReadLine().Split().Select(long.Parse).ToArray(); }
        static public List<long> Slist() { return ReadLine().Split().Select(long.Parse).ToList(); }

        static readonly long Mod = 1000000000 + 7;

        static void Main(string[] args)
        {
            //SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
            var S = ReadLine();
            var keyence = "keyence";
            // 場合分け
            //  ・最初か最後が"keyence"
            //  ・最初がk～末尾に残り
            //  他の場合、一つの部分列の削除では"keyence"にならない
            // 最初か最後が"keyence"
            if (S.Substring(0, keyence.Length) == keyence || S.Substring(S.Length - keyence.Length) == keyence)
            {
                WriteLine("YES");
                return;
            }
            // 最初がkで残りが末尾
            if (S[0] == keyence[0])
            {
                var cnt = 0;
                while (S[cnt] == keyence[cnt])
                    ++cnt;
                if (keyence.Substring(cnt) == S.Substring(S.Length - (keyence.Length - cnt)))
                {
                    WriteLine("YES");
                    return;
                }
            }
            WriteLine("NO");

            //Out.Flush();
        }
    }
}