#include <bits/stdc++.h>
using namespace std;
int n;
int a[1005][1005];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n;
  for (int i = 1; i <= n; i++) a[1][i] = a[i][1] = 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];
  cout << a[n][n];
  return 0;
}
