create 3 columns with rows filled by Single Value yes… medium … no
create 3 IF/ELSE column to check if grade column is one of these columns…
than 3 roll up columns to to sum these IF/ELSE columns…
you will know not only if at least 1 yes 1 medium 1 no is there… you will know exactly how many
For this I would normally create a template joining Title and YES together. Then create a self relation linking that template back to itself. If the relation is not empty, then the project has at least one YES.