So you want to divide it by all of the different ways that you can swap 2 different things. If we had 3 heads here, you would think about all of the different ways that you could swap 3 different things. If we had 4 heads here, it would be all of the different ways you could swap 4 different things. So there's 12 different scenarios if you couldn't swap them, but you want to divide it by all of the different ways that you can swap 2 things. So 12 divided by 2 is equal to 6 fundamentally different scenarios, considering that you can swap them. If you assume that head A and head B can be interchangeable, that it's a completely identical outcome for us, because they're really just heads. So there's 6 different scenarios, and we know that there's a total of 16 equally likely scenarios.