#include <bits/stdc++.h>
using namespace std;
int a[11][11];
int main() {
  int n;
  memset(a, 0, sizeof(a));
  for (int i = 1; i <= 10; ++i) a[1][i] = 1;
  for (int i = 2; i <= 10; ++i) {
    a[i][1] = 1;
    for (int j = 2; j <= 10; ++j) a[i][j] = a[i - 1][j] + a[i][j - 1];
  }
  while (cin >> n) cout << a[n][n] << endl;
  return 0;
}
