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.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String s = in.readLine();
    int n = s.length();
    //Sの1文字目から(N-1)/2文字目までからなる文字列
    String s_sub_bf = s.substring(0,n/2);
    StringBuffer sb_bf = new StringBuffer(s_sub_bf);
    String s_rev_bf = sb_bf.reverse().toString();
    //Sの(N+3)/2文字目からN文字目までからなる文字列
    String s_sub_af = s.substring((n+2)/2,n);
    StringBuffer sb_af = new StringBuffer(s_sub_af);
    String s_rev_af = sb_af.reverse().toString();
    System.out.println(s_sub_bf.equals(s_rev_bf) && s_sub_af.equals(s_rev_af)?
                       "Yes":"No");
  }
}