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 Perl (v5.18.2) (judge verdict: Wrong Answer)

chomp($str = <STDIN>);
@str = ("", split(//, $str));

$n = scalar(@str) / 2;
$a = join("", @str[1 .. $n - 1]);
$b = join("", reverse(@str[$n + 1 .. $#str]));

if($a ne $b){
	print "No\n";
	exit;
}

$n = (scalar(@str) - 2) / 2;
$a = join("", @str[1 .. $n]);
$n = (scalar(@str) + 2) / 2;
$b = join("", @str[$n .. $#str]);

for $one (split(/,/, "$a,$b")){

	$n = (length($one) + 1) / 2;
	$a = substr($one, 0, $n - 1);
	$b = substr($one, $n, length($one) - 1);
	
	if($a ne $b){
		print "No\n";
		exit;
	}

}

print "Yes\n";