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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
import java.io.*;


public class Main {
    private static boolean checkP(String s, int start, int end) {
        int sum = start + end, limit = (sum % 2 == 0) ? ((sum / 2) - 1) : ((sum / 2));
        for(int i = start, j = end; i <= limit; i++, --j) {
            if(s.charAt(i) != s.charAt(j)) return false;
        }
        return true;
    }
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.next();
        int N = s.length();
        boolean flag = checkP(s, 0, ((N - 1)/2) - 1) && checkP(s, ((N + 3)/2) - 1, N - 1);
        System.out.println(flag ? "Yes" : "No");
    }
}