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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <string>

using namespace std;

bool batch(string str){
  string str1 = str.substr(0, str.size()/2);
  string str2 = str.substr((str.size()+1)/2);
  reverse(str2.begin(), str2.end());
  if(equal(str1.begin(), str1.end(), str2.begin())){
    return true;
  }
  return false;
}

int main(){
  string S;
  cin >> S;
  
  //cout << S << endl;
  
  string ans;
  string str1 = S.substr(0, S.size()/2);
  string str2 = S.substr((S.size()+1)/2);
  
  //cout << str1 << endl;
  
  if(batch(S) && batch(str1) && batch(str2)){
    ans = "Yes";
  }else{
    ans = "No";
  }
  
  cout << ans << endl;
}