#include <bits/stdc++.h>
using namespace std;
long long fac(long long n) {
  if (n == 1 || n == 0) {
    return 1;
  }
  return n * fac(n - 1);
}
int main() {
  long long n;
  cin >> n;
  cout << (fac(n - 1) * 2) / n << "\n";
}
