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)

#coding:utf-8
s = input()
n = len(s)
half = (n-1)//2
half_1 = half // 2
m = n - (n+3)//2
l = (n+3)//2 -1
half_2 = m // 2

#sが回文か
if s[:half] == s[-1:half:-1]:
    #print(s[:half], s[-1:half:-1])
    print('Yes')
    exit()

elif half % 2 != 0 and s[:half_1] == s[half-1:half_1:-1]:
    #print(half_1)
    #print(s[:half_1], s[half-1:half_1:-1])
    print('Yes')
    exit()

elif half % 2 == 0 and s[:half_1] == s[half:half_1:-1]:
    print('Yes')
    exit()

elif (m-1) % 2 != 0 and s[l:l+half_2] == s[-1:l+half_2+1:-1]:
    #print(l+half_2)
    #print(s[l:l+half_2], s[l+half_2+1:])
    print('Yes')
    exit()

elif (m-1) % 2 == 0 and s[l:l+half_2] == s[-1:l+half_2:-1]:
    print('Yes')
    exit()


print('No')