#include <bits/stdc++.h>
using namespace std;
long long Cruz(int a, int b) {
  long long p1 = 1, p2 = 1;
  for (int i = 0; i < b; i++) p1 *= a - i;
  for (int i = 0; i < b; i++) p2 *= i + 1;
  return p1 / p2;
}
int main() {
  int n;
  cin >> n;
  if (n >= 1 && n <= 10) {
    cout << Cruz(2 * n - 2, n - 1);
  }
  return 0;
}
