#include <bits/stdc++.h>
using namespace std;
long long cal_n(long long n) {
  long long temp = 1;
  for (long long i = 2; i <= n; i++) temp = temp * i;
  return temp;
}
long long nCr(long long n, long long r) {
  return cal_n(n) / (cal_n(r) * cal_n(n - r));
}
void solve() {
  long long n;
  cin >> n;
  long long m = n - 1;
  long long ans = nCr(2 * m, m);
  cout << ans;
  return;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  solve();
  return 0;
}
