#include <bits/stdc++.h>
using namespace std;
long long c[30][30];
long long ncr(long long n, int r) {
  if (r == 1) return n;
  if (r == 0 || r == n) return 1;
  if (c[n][r] != 0) return c[n][r];
  return c[n][r] = ncr(n - 1, r) + ncr(n - 1, r - 1);
}
long long fac[21];
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  long long n;
  cin >> n;
  fac[0] = 1;
  for (long long i = 1; i <= 10; i++) fac[i] = fac[i - 1] * i;
  long long ans = ncr(n, n / 2) / 2;
  ;
  ans *= fac[n / 2 - 1] * fac[n / 2 - 1];
  cout << ans << endl;
}
