Multiple Counting

Hi folks,

I have an intellectually simple, but nonetheless demanding question regarding an Excel-formula to count "questions" (see attached sheet for reference).
In the example I have five different subjects (A to E). There is a list of questions (A2:A28). Questions relate to the different subjects. E.g., Q1 is relevant for each subject.
This is the basis.

Now we have persons, that can chose subjects. In the example, person A has chosen subjects A and C, person B has chosen A and B and so on.

Since certain questions are identical between the different subjects, a person just needs to answer "unique questions". This means, that if e.g., person A has answered question 1 because it is included in subject A, he/she doen't have to answer it again in subject C.

Therefore the different persons have to answer a sum X questions, which I have counted manually now (cells N2:N5).
I am looking for an easy formula to automatically count the number of questions a person has to answer based on the subjects it has chosen.

Thanks a lot in advance for any input.

i would suggest rearranging your data to make it more intuitive, but here is one way... not quick though. With this you can put X's in the table to change the aswers

@FlameRetired: perfect, the formula seems to work. I must have miscounted myself and double checked. The formula's results are fine.