#include <bits/stdc++.h>
using namespace std;
template <typename T>
using vec = vector<T>;
template <typename T>
using graph = vec<vec<T> >;
template <typename T, typename V = vector<T>, typename C = less<T> >
using pQ = priority_queue<T, V, C>;
template <typename T>
void cinVec(vec<T> &v) {
  for (int i = 0; i < v.size(); i++) {
    cin >> v[i];
  }
}
template <typename T>
void cinVec(vec<T> &v, unsigned long long int n) {
  v.resize(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
  }
}
template <typename T>
ostream &operator<<(ostream &os, vec<T> &v) {
  for (int i = 0; i < v.size(); i++) {
    os << v[i];
  }
  return os;
}
template <typename T>
istream &operator>>(istream &is, vec<T> &v) {
  for (int i = 0; i < v.size(); i++) {
    is >> v[i];
  }
  return is;
}
template <typename T, typename C>
void cinPq(priority_queue<T, vector<T>, C> &q, unsigned long long int n) {
  for (int i = 0; i < n; i++) {
    T e;
    cin >> e;
    q.push(e);
  }
}
unsigned long long int fact(unsigned long long int n) {
  return n == 1 || n == 0 ? 1 : n * fact(n - 1);
}
void solve() {
  unsigned long long int n;
  cin >> n;
  cout << fact(n) / fact(n / 2) / fact(n / 2) / 2 * fact(n / 2 - 1) *
              fact(n / 2 - 1)
       << "\n";
}
int main() {
  int T = 1;
  while (T--) {
    solve();
  }
  return 0;
}
