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.*;

class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		String s = in.next();
		int len = s.length();
		StringBuilder sb = new StringBuilder();
		sb.append(s);
		StringBuilder sub1 = new StringBuilder();
		sub1.append(sb.substring(0,len/2));
		StringBuilder sub2 = new StringBuilder();
		sub2.append(sb.substring(len/2+1));
		if(sb.toString().contentEquals(sb.reverse()) && 
		   sub1.toString().contentEquals(sub1.reverse()) &&
		   sub2.toString().contentEquals(sub2.reverse())){
			System.out.println("Yes");
		} else{
			System.out.println("No");
		}
	}
}