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 PyPy3 (2.4.0) (judge verdict: Accepted)

GI = lambda: int(input()); GIS = lambda: map(int, input().split()); LGIS = lambda: list(GIS())

def is_palindrome(s):
    l = 0
    r = len(s) - 1

    while l < r:
        if s[l] != s[r]:
            return False
        l += 1
        r -= 1

    return True

def main():
    s = input()
    n = len(s)
    print(('No', 'Yes')[(is_palindrome(s) and is_palindrome(s[:n//2]) and is_palindrome(s[n//2+1:]))])

main()