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()

left = 0
left_end = (len(S)-1)//2 -1
right = len(S)-1
right_start = (len(S)+3)//2 -1
flag = 0

for i in range((len(S)-1)//2):
	if(S[left] != S[right]) or (S[left] != S[left_end]) or (S[right_start] != S[right]):
		flag += 1
		break
	left += 1
	left_end -= 1
	right_start += 1
	right -= 1

if flag == 0:
	print("Yes")
else:
	print("No")