#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
const int inf = 0x3f3f3f3f;
int n, m, k;
int x, y;
long long ans[] = {0,
                   1,
                   3,
                   40,
                   1260,
                   72576,
                   6652800,
                   889574400,
                   163459296000,
                   39520825344000,
                   12164510040883200};
void solve(int T) {
  cin >> n;
  cout << ans[n / 2] << '\n';
}
int main() {
  std::ios::sync_with_stdio(false);
  cin.tie(NULL);
  int numoftest = 1;
  for (int siven = 1; siven <= numoftest; ++siven) solve(siven);
  return 0;
}
