#include <bits/stdc++.h>
using namespace std;
int n, res = 0, a[11][11];
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) a[i][1] = a[1][i] = 1;
  for (int i = 2; i <= n; i++)
    for (int j = 2; j <= n; j++) a[i][j] = a[i - 1][j] + a[i][j - 1];
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++) res = max(res, a[i][j]);
  cout << res;
}
