Counting formulas on a separate tab based on filtering a column by the text in a cell

Good evening once again. I am using Office 365. Please see attached. I'm trying to do this:

Depending on the text in USE:B2, filter SITES: B:B by that text, then count cells in SITES: P:P which are formulas.

I know how to count formulas on a separate tab....

I know how to filter a column on a separate tab based on text in a cell....

But I don't know how to do both at the same time.