One.
How many pessimists does it take to change a light bulb? None - it's probably screwed it too tight anyhow!
Just one... But it takes 4 episodes and Krillin dies...
One. He puts the bulb in and lets the world revolve around him.
None, they don't use light bulbs. They live in caves and use no forms of artificial energy because they wouldn't want to be perceived as hypocrites or morons.
To get to the other side!
