#include <bits/stdc++.h>
using namespace std;
long long int mod = 10000007;
long long int a[200][200];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int n, m, x, t, i, j, sum = 0;
  cin >> n;
  for (i = 1; i <= n; i++)
    for (j = 1; j <= n; j++) {
      if (i == 1 || j == 1)
        a[i][j] = 1;
      else
        a[i][j] = a[i - 1][j] + a[i][j - 1];
    }
  cout << a[n][n] << "\n";
  return 0;
}
