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 (Clang 3.8.0) (judge verdict: Accepted)

#include <iostream>
#include <string>

using namespace std;

int main(int argc, const char *argv[]) {
  string S, R;
  string RSfront, RSend;
  cin >> S;
  R = S;
  string Sfront = S.substr(0, ((S.length() - 1) / 2));
  string Send = S.substr(((S.length() + 3) / 2) - 1, ((S.length() - 1) / 2));
  RSfront = Sfront;
  RSend = Send;
  reverse(R.begin(), R.end());
  reverse(RSfront.begin(), RSfront.end());
  reverse(RSend.begin(), RSend.end());

  if(S == R && Sfront == RSfront && Send == RSend){
    cout << "Yes" << endl;
  }else{
    cout << "No" << endl;
  }
  return 0;
}