[TRICKY] Distinct count

[#1]

Hi,

I have a data structure like below,

If i do Count distinct Supplier, i get my correct figure.

Year | Supplier

BUT, when i have the following, same set of data but just adding new dimension, the figure shoot up high.

How can i make an expression for this structure but to have the same supplier count as the above structure?

Year | Supplier | Functions

Thanks.