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 Ruby (2.3.3) (judge verdict: Wrong Answer)

n = gets.chomp.split("")
check = 0
count = 0
check2 = 0
if n[0] != "k"
  check2 = 1
end
for i in 0..n.length-1
  if n[i] == "k" && count == 0
    count += 1
  elsif n[i] == "e" && count == 1
    count += 1
  elsif n[i] == "y" && count == 2
    count += 1
  elsif n[i] == "e" && count == 3
    count += 1
  elsif n[i] == "n" && count == 4
    count += 1
  elsif n[i] == "c" && count == 5
    count += 1
  elsif n[i] == "e" && count == 6
    count += 1
  elsif check == 0
    check = count
  elsif check != count
    check = 0
    count = 0
  end
  if count == 7 && (check == 0 || i == n.length-1) && check2 == 0
    puts "YES"
    exit
  end
end
puts "NO"