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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
using namespace std;

int main() {
  string s;
  cin >> s;
  int s_length = 0;
  string word = "keyence";
  int i;
  if (s.length() >= word.length()) {
    for (i = 0; i < word.length(); i++) {
      if (s.at(i) != word.at(i)) {
        break;
      }
      s_length++;
    }
    if (s_length != word.length()) {
      int diff = s.length() - word.length();
      for (i = s.length() - 1; i > -1; i--) {
        if (s.at(i) != word.at(i - diff)) {
          break;
        }
        s_length++;
      }
    }
  }
  cout << (s_length == word.length() ? "YES" : "NO") << endl;
  return 0;
}