#include <bits/stdc++.h>
using namespace std;
int n;
int a[15][15];
int main() {
  int i, j;
  while (scanf("%d", &n) > 0) {
    for (i = 1; i <= n; i++) {
      for (j = 1; j <= n; j++) {
        if (i == 1) {
          a[i][j] = 1;
        } else {
          a[i][j] = a[i - 1][j] + a[i][j - 1];
        }
      }
    }
    printf("%d\n", a[n][n]);
  }
  return 0;
}
