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 JavaScript (node.js v5.12) (judge verdict: Accepted)

function main(input) {
  var S = input[0];
  var N = S.length;

  var resCount = 0;
  if(palindrome(N, S)){
  	resCount +=1;
  };
  
  var headS = S.slice(0, (N-1)/2);
  if(palindrome(headS.length, headS)){
    resCount +=1;
  }
  
  var TailS = S.slice((N +3)/2 -1, N);
  if(palindrome(TailS.length, TailS)){
    resCount +=1;
  }
  
  if(resCount === 3){
  	console.log('Yes');
  }else{
  	console.log('No');
  }  
}

function palindrome(N, S){
  
    var mid = Math.floor(N/2);
	for ( var i = 0; i < mid; i++ ) {
    if (S[i] !== S[N - 1 - i]) {
      return false;
    }
  }

  return true;
}

main(require('fs').readFileSync('/dev/stdin', 'utf8').trim().split("\n"));