#include <bits/stdc++.h>
using namespace std;
int main(int argc, char **argv) {
  int C[20][20];
  C[0][0] = 1;
  for (int i = (0); i < (20); ++i) {
    for (int j = (0); j < (20); ++j) {
      if (i == 0 || j == 0)
        C[i][j] = 1;
      else {
        C[i][j] = C[i - 1][j] + C[i][j - 1];
      }
    }
  }
  int N;
  cin >> N;
  int res = C[0][0];
  for (int i = (0); i < (N); ++i) {
    for (int j = (0); j < (N); ++j) {
      res = max(res, C[i][j]);
    }
  }
  printf("%d\n", res);
  return 0;
}
