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 {
	static boolean isPalindrome(String s){
		for(int i = 0 ; i < s.length() ; ++i){
			int j = s.length() - 1 - i;
			if(s.charAt(i) != s.charAt(j)){
				return false;
			}
		}
		return true;
	}
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String S = sc.next();
		int N = S.length();
		int M = (N - 1) / 2;
		boolean f = isPalindrome(S) & 
				    isPalindrome(S.substring(0 , M)) &
	    			isPalindrome(S.substring(M + 1));

		if(f){
			System.out.println("Yes");
		}else{
			System.out.println("No");			
		}
	}
}