I have data that is arranged as below
Column Name Col1 Col2 Col3
a b s
a c w
b d s
b c w
a d w

I want to count number of s in col3 where col1 = a and
col2 = b

I am trying to use array formula using countif and if
functions, but i am getting value#

Can some one tell me the right way to get the result

thanx