#include <bits/stdc++.h>
using namespace std;
unsigned long long int fac(unsigned long long int n) {
  return (n == 1 || n == 0) ? 1 : n * fac(n - 1);
}
unsigned long long int c(unsigned long long int n, unsigned long long int r) {
  unsigned long long int k = fac(r);
  return fac(n) / (k * k);
}
int main() {
  unsigned long long int n;
  cin >> n;
  n--;
  cout << c(2 * n, n);
  return 0;
}
