Looking for a way to enhance this sumproduct expression
to return a unique employee code count:

=SUMPRODUCT((Month_of_Occurence=$B$2)*(Month_of_O ccurence<=$B$3)*(Branch=$B10))

Suppose the expression above returns: 5

In a corresponding named range: EmpCode
(range not used in the expression as yet)
the 5 instances returned are due to eg:

Emp1
Emp2
Emp1
Emp3
Emp2

Would like to return a unique employee code count of: 3
for the 5 instances. Thanks.