#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j, n, ar[11][11] = {};
  cin >> n;
  for (i = 1; i <= n; i++) {
    for (j = 1; j <= n; j++) {
      if ((i == 1) || (i == 2 && j == 1))
        ar[i][j] = 1;
      else
        ar[i][j] = ar[i - 1][j] + ar[i][j - 1];
    }
  }
  cout << ar[n][n] << endl;
}
