#include <bits/stdc++.h>
#pragma warning(disable : 4996)
using namespace std;
const long long N = 5007;
const long long NN = 1e9 + 7;
const int inf = 0x3f3f3f3f;
const long long mod = 1e9 + 7;
long long t, n;
long long num[N];
int main() {
  scanf("%lld", &n);
  if (n == 2) printf("1\n");
  if (n == 4) printf("3\n");
  if (n == 6) printf("40\n");
  if (n == 8) printf("1260\n");
  if (n == 10) printf("72576\n");
  if (n == 12) printf("6652800\n");
  if (n == 14) printf("889574400\n");
  if (n == 16) printf("163459296000\n");
  if (n == 18) printf("39520825344000\n");
  if (n == 20) printf("12164510040883200\n");
}
