#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline void checkMin(T &a, T b) {
  if (b < a) a = b;
}
template <typename T>
inline void checkMax(T &a, T b) {
  if (a < b) a = b;
}
int main() {
  int n, a[11][11];
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    for (int j = 1; j <= n; ++j) {
      a[i][j] = i == 1 || j == 1 ? 1 : a[i - 1][j] + a[i][j - 1];
    }
  }
  printf("%d\n", a[n][n]);
  return 0;
}
