#include <bits/stdc++.h>
using namespace std;
long long C(int n, int m) {
  if (m < n - m) m = n - m;
  long long ans = 1;
  for (int i = m + 1; i <= n; i++) ans *= i;
  for (int i = 1; i <= n - m; i++) ans /= i;
  return ans;
}
int fac(int x) {
  int f;
  if (x == 0 || x == 1)
    f = 1;
  else
    f = fac(x - 1) * x;
  return f;
}
int main() {
  int n;
  cin >> n;
  long long ans = 0;
  ans = C(n, n / 2) / 2 * fac(n / 2 - 1) * fac(n / 2 - 1);
  cout << ans;
}
