#include <bits/stdc++.h>
using namespace std;
int main() {
  int aa[10][10];
  for (int j = 0; j < 10; j++) {
    aa[0][j] = 1;
    aa[j][0] = 1;
  }
  for (int l = 1; l < 10; l++) {
    for (int t = 1; t < 10; t++) {
      aa[l][t] = aa[l - 1][t] + aa[l][t - 1];
    }
  }
  int i;
  while (cin >> i) {
    cout << aa[i - 1][i - 1];
  }
}
