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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php

fscanf(STDIN, "%s", $s);
$word = "keyence";
$len = strlen($s);
if (strpos($s, $word) === '0') {
	echo "YES";
	exit;
}else if (strpos($s, $word) === $len - 7) {
	echo "YES";
	exit;
}
for ($i=1; $i < 7; $i++) { 
	$key  = substr($word, 0, $i);
	$ence = substr($word, $i-7);
	if (strpos($s, $key) === '0' && strpos($s, $ence, $i - 7) == $len + $i - 7) {
		echo "YES";
		exit;
	}
}

echo "NO";