#include <bits/stdc++.h>
using namespace std;
int a[12][12];
int main() {
  int n, i, j;
  while (scanf("%d", &n) != EOF) {
    int maxi = 1;
    for (i = 1; i <= n; i++) a[i][1] = a[1][i] = 1;
    for (i = 2; i <= n; i++) {
      for (j = 2; j <= n; j++) {
        a[i][j] = a[i - 1][j] + a[i][j - 1];
        maxi = max(maxi, a[i][j]);
      }
    }
    cout << maxi << endl;
  }
  return 0;
}
