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 12.16.1) (judge verdict: Accepted)

"use strict";

const is_palindrome = s => {
    let n = s.length;
    for (let i = 0; i < n; i++) {
        if (s[i] !== s[n - i - 1]) return false;
    }

    return true;
}

const main = (input) => {
    const spi = input.split('\n');
    const s = spi[0];
    const n = s.length;

    if (is_palindrome(s)
        && is_palindrome(s.substring(0, (n-1)/2))
        && is_palindrome(s.substr((n+3)/2-1)))
        console.log("Yes");
    else
        console.log("No");
};

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