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: Accepted)

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.next();
        int n = s.length();
        
        boolean isStrong = true;
        
        for(int i=0; i<n; i++) {
            if(s.charAt(i) != s.charAt(n-i-1)) {
                isStrong = false;
                break;
            }
        }
        
        int n2 = (n-1)/2;
        for(int i=0; i<n2; i++) {
            if(s.charAt(i) != s.charAt(n2-i-1)) {
                isStrong = false;
                break;
            }
        }
        
        int n3 = (n+3)/2;
        for(int i=n3-1; i<n; i++) {
            if(s.charAt(i) != s.charAt(n-i+n3-1-1)) {
                isStrong = false;
                break;
            }
        }
        
        System.out.println(isStrong?"Yes":"No");
    }
}