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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

int main(){
  string S;
  cin >> S;
  
  bool a = true;
  bool b = true;
  
  int E = (S.size()-1) / 2 - 1;
  for(int i = 0; i < E; i++){
    if(S.at(i) != S.at(E-i)){
      a = false;
    }
  }
  
  int F = (S.size()+3) / 2 -1;
  for(int i = F; i < S.size(); i++){
    int c = S.size() - i;
    if(S.at(i) != S.at(S.size()-c)){
      b = false;
    }
  }
  
  if(a && b){
    cout << "Yes" << endl;
  }
  else{
    cout << "No" << endl;
  }
}