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.*;
public class Main{
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		String S = sc.next();
		int len = S.length() - 1;
		String buf = S.substring(0,(len / 2));
		String buf2 = S.substring(((len + 2) / 2),len + 1);
		String ans = "No";
		if(checkRet(S) && checkRet(buf) && checkRet(buf2)){
			ans = "Yes";
		}
		System.out.println(ans);
	}
	public static boolean checkRet(String s){
		int len = s.length() - 1;
		int n = len / 2;
		for(int i = 0;i < n;i++){
			if(s.charAt(i) != s.charAt(len - i)){
				return false;
			}
		}
		return true;
	}
}