#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  long long n;
  cin >> n;
  long long a[n + 5][n + 5];
  for (long long i = 1; i <= n; i++) {
    if (i == 1) {
      for (long long j = 1; j <= n; j++) {
        a[i][j] = 1;
      }
    } else {
      a[i][1] = 1;
    }
  }
  for (long long i = 2; i <= n; i++) {
    for (long long j = 2; j <= n; j++) {
      a[i][j] = a[i][j - 1] + a[i - 1][j];
    }
  }
  cout << a[n][n];
  return 0;
}
