Hi i have a worksheet with the following set up

col A = date col B = x

what I want to do is, count all items within a certain month and b
column is not empty.
ex. count all items in column A which are in november and that column b
is not empty.
I can count the number of items in november with this formula
=SUMPRODUCT(-(MONTH(a10:a500)=11),-ISNUMBER((a10:a500)))
but how do I only count the ones which there is something written in
the b column for that month.
Thanks