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 Haskell (GHC 7.10.3) (judge verdict: Wrong Answer)

import Data.Bool
import Data.List

main=getLine>>=putStrLn.bool"NO""YES".isK

isK :: String -> Bool
isK cs = go "keyence" cs
  where
    go [] _ = True
    go xxs@(x:xs) (y:ys)
        | x == y = go xs ys
        | otherwise = xxs `isInfixOf` ys