#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int arr[n];
  for (int i = 0; i < n; i++) arr[i] = 1;
  for (int i = 1; i < n; i++)
    for (int j = 1; j < n; j++) arr[j] = arr[j] + arr[j - 1];
  cout << arr[n - 1];
}
