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)

str = input()
N = len(str)
flag = 1

if(N == 3):
    print("Yes")

else:
    for i in range((N-1)//4):
        if(str[i] != str[(N-1)//2-1-i]):
            flag = 0
            break
    

    for i in range((N+3)//2-1,(N+3)//2-1 + (N-(N+3)//2+1)//2):
        if(str[i] != str[N-1 + ((N+3)//2-1) - i]):
            flag = 0
            break

        if(flag == 1):
            print("Yes")
        else:
            print("No")