I would say three. An emperor to order that the lightbulb be changed, a grandson to declare that lightbulbs are not worth changing and should be destroyed, and the grandson's advisor to ask Blair to change it for them.
You're forgetting the grandson's father. He comes up with a huge and ingenious device that will screw in the bulb for them, but Blair comes around and kicks it, destroying it. The father is then executed on the spot, and the rest of your scenario then ensues!