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>

int check(char *s, char *key){
    int i;
    for(i=0; s[i] == key[i]; i++);
// printf("%s\n",s+i);
    //return extract(s+i, key+i);
    if(strstr(s+i, key+i))
        return 1;
    else
        return 0;
}

int main() {
    int i=0;
    char s[101], *ky = "keyence";
    scanf("%s", s);
restart:
    for(; s[i] != 'k' && s[i] != '\0'; i++);
    if(!*(s+i)){
        printf("NO\n");
        return 0;
    }
    if(check(s+i, ky))
        printf("YES\n");
    else{ 
        //if(*(s+i+7) == '\0')
            printf("NO\n");
        // else{
        //     i++;
        //     goto restart;
        // }
    }
  return 0;
}