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>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define all(x) (x).begin(), (x).end()
using namespace std;
using VI = vector<int>;
using VB = vector<bool>;
using Graph = vector<vector<int>>;
using ll = long long;
using P = pair<int, int>;

int main()
{
  string s;
  cin >> s;

  string reversed;
  reversed = s;
  reverse(all(reversed));

  int length = s.size();

  string first = s.substr(0, (length - 1) / 2);
  string second = s.substr((length + 3) / 2 - 1, length - 1);

  string rfirst = first;
  reverse(all(rfirst));

  string rsecond = second;
  reverse(all(rsecond));

  if (s == reversed && first == rfirst && second == rsecond)
  {
    cout << "Yes" << endl;
  }
  else
  {
    cout << "No" << endl;
  }
}