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 = list(input())
N = len(S)
flag = True
for i in range((N+1)//2-1):
    if S[i] != S[-1-i]:
        flag = False
if N%4 == 1:
    mae = S[:((N+1)//4+2)]
elif N%4 == 3:
    mae = S[:((N+1)//4+1)]
ato = S[(N+3)//2-1:]

N = len(mae)
if N%2 == 1:
    for i in range((N+1)//2-1):
        if mae[i] != mae[-1-i]:
            flag = False
    for i in range((N+1)//2-1):
        if ato[i] != ato[-1-i]:
            flag = False
else:
    for i in range((N+1)//2):
        if mae[i] != mae[-1-i]:
            flag = False
    for i in range((N+1)//2):
        if ato[i] != ato[-1-i]:
            flag = False

if flag == True:
    print('Yes')
elif flag == False:
    print('No')