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(mojiretu):
    leg = len(mojiretu)
    if leg == 1:
        return True
    mid = (leg-1) // 2
    if len(mojiretu) % 2 == 0:
        return mojiretu[0:mid+1] == mojiretu[mid+1:]
    else:
        return mojiretu[0:mid] == mojiretu[mid+1:]

def fin():
    print('No')
    quit()

input_line = input()
if not kaibun(input_line):
    fin()

N = len(input_line)

if not kaibun(input_line[0:(N-1)//2]):
    fin()


print('Yes')