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 OCaml (4.02.3) (judge verdict: Accepted)

let () = 
  let s = read_line () in
  print_endline @@ if
    List.exists (( = ) "keyence") @@
    List.concat @@ Array.to_list @@ Array.init (String.length s + 1) @@ fun i ->
      Array.to_list @@ Array.init (String.length s + 1) @@ fun j ->
        if j < i then "" else String.sub s 0 i ^ String.sub s j (String.length s - j)
  then "YES" else "NO"