#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n;
  cin >> n;
  if (n == 2) {
    cout << 1 << endl;
    return 0;
  } else if (n == 4) {
    cout << 3 << endl;
    return 0;
  }
  long long int p = n / 2;
  long long int e = 1;
  for (int i = 1; i <= p; i++) {
    e = e * i;
  }
  long long int w = 1;
  for (int i = p + 1; i <= n; i++) {
    w = w * i;
  }
  long long int q = 1;
  for (int i = 1; i < p; i++) {
    q = q * i;
  }
  q = q * q;
  q /= 2;
  w /= e;
  cout << w * q << endl;
}
