#include <bits/stdc++.h>
int main() {
  int n, arr[10][10] = {
             {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
             {1, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
             {1, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
             {1, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
             {1, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {1, 0, 0, 0, 0, 0, 0, 0, 0, 0}};
  int i;
  register int j;
  scanf("%d", &n);
  for (i = 1; i < n; i++) {
    for (j = 1; j < n; j++) {
      arr[i][j] = arr[i - 1][j] + arr[i][j - 1];
    }
  }
  printf("%d", arr[n - 1][n - 1]);
  return 0;
}
