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