#include <bits/stdc++.h>
using namespace std;
int a[10][10], n;
int main() {
  cin >> n;
  for (int i = 0; i < 10; i++) {
    a[0][i] = 1;
    a[i][0] = 1;
  }
  for (int i = 1; i < 10; i++)
    for (int j = 1; j < 10; j++) {
      a[i][j] = a[i][j - 1] + a[i - 1][j];
    }
  cout << a[n - 1][n - 1] << '\n';
  return 0;
}
