#include <bits/stdc++.h>
using namespace std;
int n;
int main() {
  int t = 1;
  long long fact[21];
  fact[0] = 1;
  for (long long i = 1; i < 21; i++) fact[i] = i * fact[i - 1];
  while (t--) {
    cin >> n;
    long long ans = 1;
    ans *= (fact[n] / fact[n >> 1]);
    ans /= fact[n >> 1];
    ans = (ans * fact[(n >> 1) - 1] * fact[(n >> 1) - 1]) >> 1;
    cout << ans << endl;
  }
  return 0;
}
