#include <bits/stdc++.h>
using namespace std;
bool qf = false;
long long n, i, j, a[12][12];
int main() {
  scanf("%lld", &n);
  for (i = 1; i <= n; i++) a[1][i] = a[i][1] = 1;
  for (i = 2; i <= n; i++) {
    for (j = 2; j <= n; j++) a[i][j] = a[i - 1][j] + a[i][j - 1];
  }
  printf("%lld", a[n][n]);
  return 0;
}
