A, given that B has happened. So this is saying, what's the probability, what's the probability, probability of A given B is the probability that he picks a blue garment given that he has picked a shirt. So this, the given B, that restricts our outcomes to these two. And so the probability that he's picked a blue item, well that's one out of the two equally likely ones. So there is a one-half probability that he picks a blue garment given that he's picked a shirt. And that's because there's one blue shirt and one green shirt. Now let's look at the probability of B given A. Probability of B given A.