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 Python (3.4.3) (judge verdict: Wrong Answer)

S = input()
KEYENCE = "keyence"


isKeyence = False
for start in range(99):
    i = start
    stack = 0
    p = 0
    while i < len(S):
        s = S[i]
        if s == KEYENCE[p]:
            p += 1
            if p == len(KEYENCE):
                isKeyence = True
                break
        else:
            if i > 0 and S[i-1] == KEYENCE[p-1]:
                stack += 1
                if stack > 1:
                    stack = 0
                    p = 0
                    i -= 1
        i += 1
if isKeyence:
    print("YES")
else:
    print("NO")