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<bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
int main(){
  string s;
  cin >> s;
  string f=s;
  int n=s.size();
  reverse(f.begin(),f.end());  
  if(s!=f){
    cout << "No" << endl;
    return 0;
  }
  string a=s.substr(0,(n-1)/2);
  string b=s.substr((n+1)/2,(n-1)/2);
  string w=a;
  reverse(w.begin(),w.end());
  if(w!=a){
    cout << "No" << endl;
    return 0;
  }
  string q=b;
  reverse(q.begin(),q.end());
  if(b!=q){
    cout << "No" << endl;
    return 0;
  }
  cout << "Yes" << endl;
}