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 sc = new Scanner(System.in);
    String S = sc.next();
    boolean anskey = false;
    if (check(S) 
    		&& check(S.substring(0,(S.length()-1)/2)) 
    		&& check(S.substring(((S.length()+3)/2) - 1))) {
    	anskey = true;
    }
    System.out.println(anskey ? "Yes" : "No");
  }
  
  public static boolean check(String s) {
	  boolean key = true;
	  int N = s.length();
	  int L = N - 1;
	  for (int i = 0; i < N/2; i++) {
		  if (s.charAt(i) != s.charAt(L)) {
			  key = false;
			  break;
		  }
		  L--;
	  }
	  return key;
  }
}