Distinct Count if item Is This

I have a data set with Owner, Collaborator Type, and Folder.   Owners can own multiple folders and each folder has a Collaborator Type of external or managed.  I'd like to be able to get a distinct count of the number of owners 3 different ways.

1. Owners who only have Managed folders
2. Owners who only have External folders
3. Owners who have both types

Right now I can sum the Distinct value of Owner+Managed or Owner+External but no idea how to count the sum of Owners that ONLY do one type or the other.  Any help is greatly appreciated.