Excel 2003 formula

[Arceedee]

I have column a2:a20. Cells in that column have either "a", "f" or "x" which
letters are used in conditional formatting so that the cell turns blue,
yellow or red.
I need to count the numbers of "a" and "f" but not "x" in one formula in a21
In a1 I will be inserting a formula =IF(a21>b1,"X","")
b1 will have a manual entry - say 5
I mention that so you know that I am limited to a21 and one formula.
Thanks

 

[Bob Phillips]

=SUM(COUNTIF(A2:A20,{"a","f"}))

 

[Gary''s Student]

In A21:

=COUNTIF(A2:A20,"a")+COUNTIF(A2:A20,"f")