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.*;

public class Main {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		String S = input.next();
		int N=S.length();
		char[] a;
		char[] b;
		int check=0;
		
		String x,y;
		x=S.substring(0,N/2);
		y=S.substring(N/2+1,N);
		if(x.equals(y)) {
			check++;
		}
		a=x.toCharArray();
		b=y.toCharArray();
		
		for(int i=0;i<x.length()/2;i++) {
			if(a[i]!=a[a.length-(i+1)]) {
				check--;
			}
		}
		for(int i=0;i<y.length()/2;i++) {
			if(b[i]!=b[b.length-(i+1)]) {
				check--;
			}
		}
		
		if(check==1) {
			System.out.println("Yes");
	    }else{
	    	System.out.println("No");
	    }		
	}		
}