#include <bits/stdc++.h>
using namespace std;
int main() {
  uint64_t n;
  cin >> n;
  uint64_t n_fact = 1;
  uint64_t n_half_fact = 1;
  for (int i = 2; i <= n; ++i) {
    n_fact *= i;
    if (i <= n / 2) {
      n_half_fact *= i;
    }
  }
  uint64_t ans = ((n_fact) / (2 * n_half_fact * n_half_fact)) *
                 ((n_half_fact) / (n / 2) * (n_half_fact) / (n / 2));
  cout << ans << '\n';
  return 0;
}
