Person 1, just for simplicity, let's imagine the case that we only have two people in the room. What's the probability that they have different birthdays? So if I have two, let's see, person 1, their birthday could be 365 days out of 365 days in the year, right? Whatever their birthday is. And then person 2, if we wanted to ensure that they don't have the same birthday, how many days could person 2 be born on? Well, it could be born on any day that person 1 was not born on. So there's 364 possibilities out of 365.