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)

# -*- coding: utf-8 -*-

S = input()
N = len(S)
left = S[:int((N-1)/2)]
right = S[int((N+3)/2-1):]

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

if is_kaibun(S) == False:
    print('No')
elif is_kaibun(left) == False:
    print('No')
elif is_kaibun(right) == False:
    print('No')
else:
    print('Yes')