#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int i = 1, j, k = 0, l, m = 0, c, n;
  cin >> n;
  int a[n][n];
  for (i = 0; i < n; i++) {
    a[0][i] = 1;
  }
  i = 0;
  for (i = 0; i < n; i++) {
    a[i][0] = 1;
  }
  for (i = 1; i < n; i++) {
    for (j = 1; j < n; j++) {
      a[i][j] = a[i][j - 1] + a[i - 1][j];
    }
  }
  cout << a[n - 1][n - 1];
}
