#include <bits/stdc++.h>
using namespace std;
using ll = long long;
ll n, fact[21];
int main() {
  fact[1] = 1;
  for (int i = 2; i <= 20; ++i) fact[i] = fact[i - 1] * i;
  cin.tie(0)->sync_with_stdio(0);
  cin >> n;
  if (n == 2) return cout << "1\n", 0;
  cout << (fact[n] / fact[n / 2] / fact[n / 2] / 2) * fact[n / 2 - 1] *
              fact[n / 2 - 1]
       << '\n';
}
