#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
uint64_t solve(int n) {
  map<int, uint64_t> ans = {{2, 1},
                            {4, 3},
                            {6, 40},
                            {8, 1260},
                            {10, 72576},
                            {12, 6652800},
                            {14, 889574400},
                            {16, 163459296000},
                            {18, 39520825344000},
                            {20, 12164510040883200}};
  return ans[n];
}
int main(int argc, char **argv) {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  cout << solve(n) << endl;
}
