Count Unique combinations of two columns

Hello Everyone,

Kindly help me with an excel formula or VBA to count distinct values. So For each ID, how many distinct Customers are there. Here is an example of what I am looking

ID Cust Distinct Count
11 A 1
11 A 1
11 A
22 D 2
22 D 2
22 C 2
33 P 3
33 Q 3
33 R 3

=SUM(IF($A$2:$A$200=A2,1/COUNTIF($B$2:$B$200,$B$2:$B$200),0))

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