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)

s = input()
flg = 0
n = len(s)
s1 = s[0:(n-1)//2]
s2 = s[(n+3)//2-1:]
t1 = s1[::-1]
t2 = s2[::-1]
#print(s1,s2,t1,t2)

for i in range(len(s1)):
  if s1[i] != t1[i] or s2[i] != t2[i]:
    flg = 1
    break
for i in range(n//2):
  if s[i] != s[-(i+1)]:
    flg = 1
    break
 
print("Yes" if flg == 0 else "No")