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()
n=len(s)
count=0
a=(n-1)//2
b=(n+3)//2
for i in range(n//2):
  if s[i]!=s[-abs(i+1)]:
    count+=1
    
for i in range(a//2):
  c=ord(s[i])
  d=ord(s[(a-1-i)])
  if c!=d:
    count+=1

for i in range((n-b+1)//2):
  c=ord(s[-(i+1)])
  d=ord(s[b-1+i])
  if c!=d:
    count+=1

if count!=0:
  print('No')
else:
  print('Yes')