Count date cells for specific month

Hi all,

I am trying to count a data range of dates to see how many of the fields have dates for a specific month.

I currently have the below, but it is displaying a #VALUE! error as there are some blank fields within the data range. I have tested without the blanks and it works fine.

=SUMPRODUCT(1*(MONTH(A4:A81)=F1))

A4:A81 is the data range of dates
F1 cell is showing a month number, 3 for example.

Please help!

Kind regards,
Brad