#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int n, a[12][12];
  cin >> n;
  memset(a, 0, sizeof(a));
  for (int i = 1; i <= n; i++) {
    a[1][i] = 1;
    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;
}
