#include <bits/stdc++.h>
using namespace std;
int main() {
  int x[10][10];
  for (int i = 0; i < 10; i++) {
    for (int j = 0; j < 10; j++) {
      if (i == 0 || j == 0)
        x[i][j] = 1;
      else
        x[i][j] = x[i - 1][j] + x[i][j - 1];
    }
  }
  int n;
  cin >> n;
  cout << x[n - 1][n - 1] << endl;
}
