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