I want to count the unique entry (Text & Numeric) based on the condition on
another corresponding row data, following is an example of data set

any Rajat
why Two
who Three
how 5
when Rajat
any 4
why Two
any Rajat
any 5
when Rajat

i want to count perticular value in colum A has how many unique entry in
Colum B.
e.g. "any" has how many unique entry in Colum B
Answer is 3 (any has value of Rajat, 4, Rajat, 5)

In this case what formula should i use, any suggestion will be of great help
to me.