So we're just left with the set that contains a 0. So all of this business right over here has simplified to a set that only contains 0. Now let's think about what B intersect C is. These are all of the things that are in both B and C. So this is going to be B intersect C. Let's see. 0 is not in both of them. 17 is in both of them. So we'll throw a 17 there.