I want to look up "DSC" in column BH, then I want to count different values
in column AC, but I only want to count the occurences of value in column AC,
if "DSC" occurs in column BH.

I tried =if(vlookup(bh8:bh550,"dsc),(countif(AC8:AC650,"X" ))

I've tried everything at this point.

If BH8:BH550 is "DSC", then count AC8:AC550,"X"

There are different values in both columns and I need a formula to perform
this function based on the "DSC" and "X" criteria, which may change to
something like "KLK" and "S".

HELP!!!