At least two, but they have to be pretty small to fit.
Just two.
How many dragon Ball z characters does it take to screw in a lightbulb? Only one, but it'll take at least 6 episodes!
It depends on the definition of lightbulb.
Just two, how did they get in there anyway?
Take the 'F' out of safe and the 'F' out of way.
Honshu!
Well, turns out one is not enough, but if you pair it, two can.
Because Americans use imperial unit system.