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: Accepted)

def kaibun(s):
    #print('[debug]',s)

    for i in range(len(s) // 2):
        if s[i] != s[len(s)-1 - i]:
            return False
    
    return True

def main():
    S = input()
    N = len(S)
    if kaibun(S) == False:
        #print('[debug]','if 1')
        print('No')
        return

    if kaibun(S[0:(N-1)//2]) == False:
        #print('[debug]','if 2')
        print('No')
        return
    if kaibun(S[(N+3)//2 - 1:N]) == False:
        #print('[debug]','if 3')
        print('No')
        return

    print('Yes')

if __name__ == '__main__':
    main()