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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <string.h>
//異なる列が前か中か後かを判定(変わるタイミングでフラグを立てる)
int main(){
  int i=0,ok=-1,change=0;
  char key[8],ch;
  strcpy(key,"keyence\0");
  while(scanf("%c",&ch)!=EOF){
    if(key[i]==ch){
      if(ok==0) change++;
      i++; 
      ok=1;
    }
    else if(ok==1){
      change++;
      ok=0;
    }
    else ok=0;
  }
  if(i==7&&((change<=2&&ok==1)||(change<=1&&ok==0)))printf("YES");
  else printf("NO");
}