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{
	const int mod=1000000007;
	static void Main(){
		string k="keyence";
		string s=Console.ReadLine();
		string ans="NO";
		for(int i=0;i<=s.Length-7;i++){
			if(s[i]=='k'){
				int q=0;
				for(int j=7;j>0;j--){
					if(s.Substring(i,j)==k.Substring(0,j)){
						q=j;
						break;
					}
				}
				for(int j=i+q;j<=s.Length-(7-q);j++){
					if(s.Substring(j,7-q)==k.Substring(q,7-q)){
						ans="YES";
						break;
					}
				}
			}
		}
		Console.WriteLine("{0}",ans);
	}
}