#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cout << name << " = " << arg1 << '\n';
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cout.write(names, comma - names) << " = " << arg1 << " ";
  __f(comma + 1, args...);
}
long long int ceil(long long int a, long long int b) { return (a + b - 1) / b; }
void solve() {
  long long int n, temp, ans = 0;
  cin >> n;
  long long int f = 1;
  for (long long int i = n / 2 + 1; i < (long long int)n + 1; i++) f *= i;
  for (long long int i = 1; i < (long long int)n / 2 + 1; i++) f /= i;
  f /= 2;
  for (long long int i = 1; i < (long long int)n / 2; i++) f *= i;
  for (long long int i = 1; i < (long long int)n / 2; i++) f *= i;
  cout << f << '\n';
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int Test = 1;
  while (Test--) {
    solve();
  }
  return 0;
}
