Well, three people haven't sat down yet, so there's three possibilities there. So now there's five times four times three scenarios for seating the first three people. How many people are left for seat four? Well, two people haven't sat down yet, so there's two possibilities. So now there's five times four times three times two scenarios of seating the first four seats. And for each of those, how many possibilities are there for the fifth seat? Well, for each of those scenarios, we only have one person who hasn't sat down left, so there's one possibility.