Problem:
Score : 200 points

Problem Statement

A string S of an odd length is said to be a strong palindrome if and only if all of the following conditions are satisfied:

S is a palindrome.

Let N be the length of S. The string formed by the 1-st through ((N-1)/2)-th characters of S is a palindrome.

The string consisting of the (N+3)/2-st through N-th characters of S is a palindrome.

Determine whether S is a strong palindrome.

Constraints

S consists of lowercase English letters.

The length of S is an odd number between 3 and 99 (inclusive).

Input

Input is given from Standard Input in the following format:

S

Output

If S is a strong palindrome, print Yes;
otherwise, print No.

Sample Input 1

akasaka

Sample Output 1

Yes

S is akasaka.

The string formed by the 1-st through the 3-rd characters is aka.

The string formed by the 5-th through the 7-th characters is aka.
All of these are palindromes, so S is a strong palindrome.

Sample Input 2

level

Sample Output 2

No

Sample Input 3

atcoder

Sample Output 3

No

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

S = input()
N = len(S)
a = N % 4
ans = "Yes"
if N == 3:
    if S[0] != S[2]:
        ans = "No"
elif a == 1:
    x = (N - 1) / 4
    x = int(x)
    for i in range(x):
        if (S[i] != S[2 * x - i - 1]) or (S[2 * x + 1 + i] != S[N - 1 - i]):
            ans = "No"
elif a == 3:
    x = (N - 3) / 4
    x = int(x)
    for i in range(x):
        if (S[i] != S[2 * x - i]) or (S[2 * x + 2 + i] != S[N - 1 - i]):
            ans = "No"
print(ans)