#include <bits/stdc++.h>
using namespace std;
long long a[11] = {0,
                   1,
                   3,
                   40,
                   1260,
                   72576,
                   6652800,
                   889574400,
                   163459296000,
                   39520825344000,
                   12164510040883200};
int main() {
  int x;
  cin >> x;
  cout << a[x / 2];
  return 0;
}
