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;
class Program{
    static void Main(){
        string s = Console.ReadLine();
        int n = s.Length - 7;
        for (int i = 0;i <= n;i++){
            List<char> l = new List<char>();
            for (int j = 0;j < i;j++)
                l.Add(s[j]);
            for (int j = i + n;j < s.Length;j++)
                l.Add(s[j]);
            bool f = true;
            string s2 = "keyence";
            for (int j = 0;j < 7;j++)
                f = f && s2[j] == l[j];
            if (f){
                Console.WriteLine("YES");
                return;
            } 
        }
        Console.WriteLine("NO");
    }
}