#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9 + 7;
const float PI = 3.14159265358;
long long a[11] = {
    1,       3,         40,           1260,           72576,
    6652800, 889574400, 163459296000, 39520825344000, 12164510040883200};
int n;
int main() {
  ios::sync_with_stdio(0), cin.tie(NULL), cout.tie(NULL);
  ;
  cin >> n;
  cout << a[n / 2 - 1];
}
