#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, arr[10][10];
  cin >> n;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if (i == 0) {
        arr[i][j] = 1;
      } else if (j == 0) {
        arr[i][j] = 1;
      } else {
        arr[i][j] = arr[i - 1][j] + arr[i][j - 1];
      }
    }
  }
  cout << arr[n - 1][n - 1];
  return 0;
}
