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: Wrong Answer)

'use strict';
function main(input) {
  const arr = input.trim().split('\n')[0];
  const howLong = arr.length;
  let isStrong = false;
  let isKaibun = false;

  if (kaibun(howLong)) {
    if (kaibun((howLong - 1) / 2)) {
      if (kaibun(howLong+ 3) / 2) {
        isStrong = true;
      }
    }
  }
  
  function kaibun (howLong) {
    for (let i = 0; i < (howLong / 2); i ++) {
      if (arr[i] !== arr[howLong - 1]) {
        return;
      }
      return isKaibun = true;
    }
  }

  console.log(isStrong ? 'Yes' : 'No');
}


main(require("fs").readFileSync("/dev/stdin", "utf8"));