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.Text.RegularExpressions;

class Program
{
  static void Main()
  {
    string S = Console.ReadLine();
    if (S == "keyence") Console.WriteLine("YES");
    else if ((Regex.IsMatch(S, @"^keyence")) || (Regex.IsMatch(S, @"keyence$")) ||
    (Regex.IsMatch(S, @"^k") || (Regex.IsMatch(S, @"eyence$"))) ||
    (Regex.IsMatch(S, @"^ke") || (Regex.IsMatch(S, @"yence$"))) ||
    (Regex.IsMatch(S, @"^key") || (Regex.IsMatch(S, @"ence$"))) ||
    (Regex.IsMatch(S, @"^keye") || (Regex.IsMatch(S, @"nce$"))) ||
    (Regex.IsMatch(S, @"^keyen") || (Regex.IsMatch(S, @"ce$"))) ||
    (Regex.IsMatch(S, @"^keyenc") || (Regex.IsMatch(S, @"e$"))))
    {
      Console.WriteLine("YES");
    }
    else Console.WriteLine("NO");
  }
}