#include <bits/stdc++.h>
using namespace std;
int n, a[11][11];
int main() {
  cin >> n;
  a[0][1] = 1;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) a[i][j] = a[i - 1][j] + a[i][j - 1];
  }
  cout << a[n][n];
  return 0;
}
