#include <bits/stdc++.h>
using namespace std;
void printArray(int a[], int n) {
  for (int i = 0; i < (n); ++i) cout << a[i] << " ";
  cout << "\n";
}
void printVec(vector<int> v) {
  int s = v.size();
  for (int i = 0; i < (s); ++i) cout << v[i] << " ";
  cout << "\n";
}
void printBool(bool b) {
  if (b)
    cout << "YES\n";
  else
    cout << "NO\n";
}
long long int fact(int n);
long long int nCr(int n, int r) { return fact(n) / (fact(r) * fact(n - r)); }
long long int fact(int n) {
  long long int res = 1;
  for (int i = 2; i <= n; i++) res = res * i;
  return res;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int n;
  cin >> n;
  ;
  cout << nCr(n, n / 2) * fact(n / 2 - 1) * fact(n / 2 - 1) / 2;
  return 0;
}
