#include <bits/stdc++.h>
const long long mod = 1e9 + 7;
using namespace std;
int c = 0;
void solve() {
  int n, k = 0;
  cin >> n;
  vector<vector<int>> a(10, vector<int>(10, -1));
  a[0][0] = 1;
  for (int i = 1; i < 10; i++) {
    a[0][i] = 1;
    a[i][0] = 1;
  }
  for (int i = 1; i < n; i++) {
    for (int j = i; j < n; j++) {
      a[i][j] = a[i - 1][j] + a[i][j - 1];
      a[j][i] = a[i][j];
    }
  }
  cout << a[n - 1][n - 1] << endl;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  int q = 1;
  while (q--) {
    c++;
    solve();
  }
}
