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;

namespace Algorithm
{
    class Program
    {
        static void Main(string[] args)
        {
            var s = Console.ReadLine();
            var keys = "keyence";

            var count = 0;
            var cur = 0;
            for (var i = 0; i < s.Length; i++)
            {
                if (s[i] == keys[count])
                    count++;
                else
                {
                    cur = i;
                    break;
                }

                if (count == keys.Length)
                {
                    Console.WriteLine("YES");
                    return;
                }
            }

            var minCount = 6;
            for (var i = s.Length - 1; i > cur; i--)
            {
                if (s[i] == keys[minCount])
                {
                    minCount--;
                    count++;
                }
                else
                    break;

                if (count == keys.Length)
                {
                    Console.WriteLine("YES");
                    return;
                }
            }

            Console.WriteLine("NO");
        }
    }
}