Count function?

[Zakynthos]

If Col A contains a text variable and column B contains a numerical variable
associated with the text variable, what is the simplest formula I can put
into a single cell that will count the number of occurrences of the numerical
variables in Col B associated with the text variable in A?

 

[Gary''s Student]

For example:

dog 3
cat 2
bat 3
rat 1
hat 1
dog 1
cat 1
bat 2
rat 2
hat 2
dog 3
cat 3
bat 2
rat 3
hat 3

=SUMPRODUCT(--(A1:A15="dog"),--(B1:B15=3))
will return a 2