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)

// We only fail when we stop trying
#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define endl '\n'
#define D(x) cerr << #x << " = " << (x) << '\n'
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()

bool pal(string s) {
  for(int i = 0 ; i < sz(s) / 2 ; i++)
    if(s[i] != s[sz(s) - 1 - i])
      return false;
  return true;
}


int main()
{
  string s;
  cin >> s;
  int n = sz(s);
  if(pal(s) && pal(s.substr(0, n / 2)) && pal(s.substr(n / 2 + 1, n / 2)))
    cout << "Yes" << endl;
  else cout << "No" << endl;
  return 0;
}