#include <bits/stdc++.h>
using namespace std;
int a[10 + 10][10 + 10];
int main() {
  int n;
  scanf("%d", &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];
  cout << a[n][n] << endl;
}
