int stepPerms(int n)
{
  vector<int> ring{1, 2, 4};
  if (n < 4) {
    return ring[n - 1];
  }
  int p = 2;
  for (int i = 4; i <= n; i++) {
    p = (p + 1) % 3;
    ring[p] = ring[0] + ring[1] + ring[2];
  }

  return ring[p];
}