#include <bits/stdc++.h>
using namespace std;
int main() {
  long long x, z, ar[100000] = {1}, sum = 0, res = 0;
  cin >> x;
  for (int i = 0; i < x; i++) {
    ar[i] = 1;
  }
  for (int i = 2; i <= x; i++) {
    for (int j = 1; j <= x; j++) {
      sum += ar[j];
      ar[j] = sum;
    }
    sum = 0;
  }
  cout << ar[x] + 1;
  return 0;
}
