#include <bits/stdc++.h>
using namespace std;
int N;
long a = 1;
long long int A[10] = {
    1,       3,         40,           1260,           72576,
    6652800, 889574400, 163459296000, 39520825344000, 12164510040883200};
int main() {
  cin >> N;
  cout << A[N / 2 - 1];
  return 0;
}
