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>
#include<cstdio>
#include <cstring>
#include <map>
#define maxn 3000000+5
using namespace std;
const long long mod = 200907;
int main()
{
    string t="keyence";
    int f=0;
    string s;cin>>s;
    int n=s.size();int flag1=0,flag2=0;
    for(int i=0;i<n;i++){
        if(s[i]==t[f]){f++;flag1=1;}
        else if(flag1==1){
            flag2++;
            flag1=0;
        }
    }
    if(f==t.size()&&flag2<=1)printf("YES");
    else printf("NO");

    return 0;
}