What's this green area? Well, that means if these are all the cases where someone shares a birthday with someone else, these are all the areas where no one shares a birthday with anyone. Or you could say all 30 people have different birthdays. So we're trying to figure out, this is what we're trying to figure out, the probability, I'll just call it the probability that someone shares. I'll call it the probability of sharing, probability of s. If this whole area is area 1 or area 100%, this green area right here, this is going to be 1 minus p of s. Or if we said that this is the probability, or another way we could say it, actually this is the best way to think about it. If this is different, so this is the probability of different birthdays. This is the probability that all 30 people have 30 different birthdays, right?