#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  int a[15][15];
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    a[i][1] = 1;
    a[1][i] = 1;
  }
  for (int i = 2; i <= n; i++)
    for (int j = 2; j <= n; j++) a[i][j] = a[i - 1][j] + a[i][j - 1];
  printf("%d\n", a[n][n]);
}
