#include <bits/stdc++.h>
using namespace std;
int arr[11][11];
int main() {
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    arr[1][i] = 1;
  }
  for (int i = 2; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      arr[i][j] = arr[i - 1][j] + arr[i][j - 1];
    }
  }
  cout << arr[n][n] << endl;
  return 0;
}
