#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 5;
template <class T>
void read(vector<T> &arr) {
  for (auto &x : arr) cin >> x;
}
template <class T>
void read(T &x) {
  cin >> x;
}
template <class T>
void write(vector<T> &arr) {
  for (auto x : arr) cout << x << " ";
  cout << "\n";
}
template <class T>
void write(vector<vector<T>> &arr) {
  for (auto &x : arr) {
    for (auto &y : x) cout << y << " ";
    cout << "\n";
  }
}
template <class T>
void write(T &x) {
  cout << x;
}
long long fact(long long n) {
  if (n == 0) return 1;
  if (n > 0) return n * fact(n - 1);
}
long long NCR(long long n, long long k) {
  if (k > n) return 0;
  if (k * 2 > n) k = n - k;
  if (k == 0) return 1;
  long long result = n;
  for (long long i = 2; i <= k; ++i) {
    result *= (n - i + 1);
    result /= i;
  }
  return result;
}
void solve() {
  long long n;
  cin >> n;
  long long x = NCR(n, n / 2) / 2;
  long long y = fact((n / 2) - 1) * fact((n / 2) - 1);
  cout << x * y;
}
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  long long t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
