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;
  string k = "keyence";
  int rmcnt = 0;
  int l = 0;
  for(int i = 0,difflag = 0;i < s.length();i++) {
    if(s[i] == 'k' && s[i+1] == 'k'&& l == 0) {
      if (difflag == 0)
        rmcnt++;
      difflag = 1;
      continue;
    }
    if(k[l] == s[i]) {
      l++;
      difflag = 0;
    }
    else if(difflag == 0) {
      difflag = 1;
      rmcnt++;
    }
  }
  if(rmcnt > 1 || k.length() != l) {
    cout << "NO" << endl;
  } else {
    cout << "YES" << endl;
  }
}