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 = list(input())
N = len(S)

sub1 = S[:(N-1)//2]
sub2 = S[(N+2)//2:]

Sc = S.copy()
sub1c = sub1.copy()
sub2c = sub2.copy()

Sc.reverse()
sub1c.reverse()
sub2c.reverse()

#print("S:{}, Sc:{}".format(S, Sc))
#print("sub1:{}, sub1c:{}".format(sub1,sub1c))
#print("sub2:{}, sub2c:{}".format(sub2,sub2c))

if S==Sc and sub1==sub1c and sub2==sub2c:
    print('Yes')
else:
    print('No')