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)

def kaibun(s):
    n = len(s)
    if n%2==0:
        S1 = s[:n//2]
        S2 = s[n//2:]
        for i in range(n//2):
            if S1[i]!=S2[i]:
                return False
        return True
    else:
        S1 = s[:n//2]
        S2 = s[n//2+1:]
        for i in range(n//2):
            if S1[i]!=S2[i]:
                return False
        return True
        
S = input()
# print(len(S))
s1 = S[:int((len(S)-1)/2)]
s2 = S[int((len(S)+3)/2-1):]

s_b = kaibun(S)
s1_b = kaibun(s1)
s2_b = kaibun(s2)

if (s_b and s1_b and s2_b):
    print("Yes")
else:
    print("No")