Whatever it says in the book.
Just one, but doing it will make them think they're going to be an electrician in the future.
Two, but don't ask me how they got in there.
NINE!
Two. One to screw in the lightbulb and another to sing about all the good times they had with the lightbulb.
The characters in this book are entirely fictional.
Barns and no-bulls. (This joke was made up by my 7 year-old cousin.)