I have a formula in Excel 2003:

=SUMPRODUCT((E10:E1740=A1858)*(F10:F1740=B1858))

Which returns the number of rows in my worksheet range where the value
in column "E" equals the value in cell "A1858" AND the value in column
"F" equals the value in cell "B1858". This formula is working well,
but not 100% of what I need.

I'd like to declare the "A1858" and "B1858" portions of the function
on the fly, using CONCATENATE("A",ROW()) and CONCATENATE("B",ROW())
instead.

So the resulting formula would be:

=SUMPRODUCT((E10:E1740=CONCATENATE("A",ROW()))*(F1 0:F1740=CONCATENATE("B",ROW())))

However, when I do this, I get a result of 0, which is wrong.

Can anyone please help me debug this error?

Thank you.