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 PHP (5.6.30) (judge verdict: Wrong Answer)

<?php 
  	$line = trim(fgets(STDIN));
	$flag1 = FALSE;
	$a = substr($line, 0, strlen($line)/2);
	$b = substr($line, (strlen($line)/2)+1, strlen($line));
	if ($a == strrev($b)) {
    	$flag1 = TRUE;
    }
	
	$flag2 = FALSE;
	$aa = substr($a, 0, strlen($a)/2);
	$ab = substr($a, (strlen($a)/2)+1, strlen($a));
	if ($aa == strrev($ab)) {
    	$flag2 = TRUE;
    }

	$flag3 = FALSE;
	$ba = substr($b, 0, strlen($b)/2);
	$bb = substr($b, (strlen($b)/2)+1, strlen($b));
	if ($ba == strrev($bb)) {
    	$flag3 = TRUE;
    }

	if ($flag1 && $flag2 && $flag3) {
    	echo "Yes\n";
    } else {
      	echo "No\n";
    }