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 = input()
n = len(s)
num = int((n-1)/2)-1
for i in range(num):
  if s[i] != s[n-1-i]:
    print("No")
    exit()
    
num = int(num /2 -1)
for i in range(num):
  if s[i] != s[n-1-i]:
    print("No")
    exit()

num = int(len(s) * 0.5 - 1.5)
index = int((n + 3) /2 )
for i in range(num):
  if s[index+i] != s[n-1-i]:
    print("No")
    exit()
   
  
print("Yes")