countif (unique entries) 2 criterias

Hello

Having some trouble deriving a formula that will
- look for account # for a county by name

there are multiple duplicates so i would only like unique entries for a county, i have attached a sample, can someone pls help!

im really out of ideas, bc countif only allows for one criteria to be searched and i use excel 03 so i cant use countifs!

i have highlighted in "red" the column that the formula should be

pls help and much appreciated!