Count the Number of Unique Values That Also Match a Value in Another Column

For example, I have a sheet to track the number of times people donated money. People occur in multiple rows in a table because they donate different amounts. I'm trying to count the number of unique people who donated who also have brown hair. This is a little different than what I'm exactly trying to do but basically the same. I'm attaching an example. I'm able to successfully do it by adding some extra columns but I'm wondering if there is a way to do it without the extra columns (Column B and C in the example), either by nesting formulas or using an array formula. This is a little over my head so would appreciate any help.