How Many Pads Could You Crash In?

Home is the place where, when you have to go there, they have to take you in.

This is true of home, but also true of relatives and certain friends.

So here's the question: How many homes could you show up at 8pm, knock on the door, and get a bed (or couch) for the night? How many of those doors belong to non-relatives? How many different cities could you do this in?