Entering main
  Entering fac
    Entering fac
      Entering fac
        Entering fac
          Entering fac
            Entering fac
              Entering fac
              Leaving  fac
            Leaving  fac
          Leaving  fac
        Leaving  fac
      Leaving  fac
    Leaving  fac
  Leaving  fac
Leaving  main