#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int** arr = new int*[n];
  for (int i = 0; i < n; i++) arr[i] = new int[n];
  for (int i = 0; i < n; i++) {
    arr[0][i] = 1;
    arr[i][0] = 1;
  }
  for (int i = 1; i < n; i++)
    for (int j = 1; j < n; j++) arr[i][j] = arr[i - 1][j] + arr[i][j - 1];
  cout << arr[n - 1][n - 1];
  return 0;
}
