Pivot table that counts when a cell includes a certain text

Hi!

I'm trying to create a pivot table that counts when a certain string is found in any given cell. For instance, I have cells with three separate values (A, B, C)in them - is there a way to make a pivot table that counts the number of times A appears as opposed to the number of times "A, B, C" appears and the number of times "A, C, D" appears, etc.? I've attached an example of what I'm working with. Thanks so much for your help!