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)

def check(s):
	l = len(s)
	c = 1

	if l != 1:

		if l % 2 == 1:
			l -= 1

		for i in range(int(l/2)):
			if s[i] != s[0-1-i]:
				c = 0

	return c

if __name__ == '__main__':
	S = input()
	LEN = len(S)
	l = int((LEN-1)/2)

	r = l+1
	s1 = S[0:l]
	s2 = S[r:LEN]

	c = check(s1) * check(s2) * check(S)

	if c == 1:
		print('Yes')
	else:
		print('No')