Hi

Hoping someone may be able to help with this one as it's driving me up the wall. I'm trying to count the number of unique occurrences of names in a list where a second condition is true

Name | Attended
----------------
Bob | Yes
Jack | No
Bob | Yes
Dave | Yes
Dave | No
Stu | Yes
Jack | No

So, regardless of the number of occurrences of a unique name in column A they would only be counted once and only be counted if they had attended at least once (corresponding "Yes" in column B). The above would filter down as

Bob
Dave
Stu

Which would produce a count of 3

I've tried using sumproduct but when adding in the condition of column B being "yes" it just doesn't add up correctly. Can anyone help?