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