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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php
$input = file_get_contents('php://stdin');
$inarr = str_split($input);

$n = count($inarr);

$front = array_slice($inarr, 0, intdiv($n-1, 2));
$back = array_slice($inarr, intdiv($n+3, 2)-1, $n-1);

if($front != array_reverse($back)){
    echo "No";
    exit();
}
if($front != array_reverse($front)){
    echo "No";
    exit();
}
if($back != array_reverse($back)){
    echo "No";
    exit();
}
echo "Yes";


?>