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)

s1 = s[0 : int((n - 1) / 2)]
s2 = s[int((n + 3) / 2 - 1) : n]

sm = int((n + 1) / 2)
s1m = int((len(s1) + 1) / 2)
s2m = int((len(s2) + 1) / 2)

if s[0 : sm - 1] == s[sm : n] \
   and s1[0 : s1m - 1] == s1[s1m : int(len(s1))] \
   and s2[0 : s2m - 1] == s2[s2m : int(len(s2))]:
    print("Yes")
else:
    print("No")