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: Accepted)

$s = <STDIN>;
chomp $s;
$N = length $s;
$flag = 0;
$A =  $s;
$B = reverse($A);
if($A ne $B ){$flag = 1;}

$T = ($N-1)/2;
$A =  substr($s, 0, $T);
$B = reverse($A);
if($A ne $B ){$flag = 1;}

$S = ($N+3)/2;
$A =  substr($s, $S-1, $T);
$B = reverse($A);
if($A ne $B ){$flag = 1;}

if($flag == 0 ){
  print "Yes";
}else{
  print "No";
}