COUNT UNIQUE OCCURENCES IF - in column A based on value of column B

Hello, I am trying to figure out how to count the unique occurrences in column A for the different labels in column B. Also I want this to work for the whole column because I will be adding to the list and do not want to adjust the formula. I can't figure out how to do this so any help would be much appreciated.

A B
SA 1 AMS
SA 1 AMS
SA 2 APJ
SA 3 APJ
SA 3 EMEA
SA 3 EMEA
SA 3 USPS



# of SA's (solution architects) in AMS (Americas), # of SA's in APJ (Asia Pacific Japan), etc.

Sorry, this was my first post -- didn't realize that would happen to the format

A.............B
SA 1........AMS
SA 1........AMS
SA 2........APJ
SA 3........APJ
SA 3........EMEA
SA 3........EMEA
SA 3.......USPS


The values should be 1 in AMS, 2 in APJ, 1 in EMEA and 1 in USPS (condensed list for example)