Count the number of Unique Items in a Column for each Unique Item in another Column

Is there any way to do a count of the number of unique items in Column B for each unique item in column A without using a helper column and a Pivot Table.

I'm using this formula in a helper column follwed by a pivot table to give me the results. I'm trying to achieve the same result without either the helper column or the pivot table in the attached sample.

=IF(SUMPRODUCT(($A$2:$A2=A2)*($B$2:$B2=B2))>1,0,1)

Many thanks