Minimum Deletions to Make Character Frequencies Unique

Already good: a=2, b=1.

Initial frequencies: a=2, b=2, c=2. All characters have the same frequency (2), so the task requires make them unique. It is possible to keep one character at frequency 2, reduce another to frequency 1, and reduce the third to frequency 0. This requires deleting 1+2=3 characters total.

Initial frequencies: a=3, b=2, c=2, e=1. Characters b and c both have frequency 2, which violates the uniqueness requirement. It is possible to keep b at frequency 2 and reduce c to frequency 1, but frequency 1 is already taken by e. So reducing c to frequency 0 by deleting 2 characters.