#include <bits/stdc++.h>
using namespace std;
int a, m[20][20];
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> a;
  for (int i = 1; i <= a; i++) {
    m[1][i] = 1;
    m[i][1] = 1;
  }
  for (int i = 2; i <= a; i++) {
    for (int j = 2; j <= a; j++) {
      m[i][j] = m[i - 1][j] + m[i][j - 1];
    }
  }
  cout << m[a][a];
}
