aaaaaaaaaa/BBBBB_ccc@00000

or

aaaaaaaaaa/BBBBB@00000

and I want the output to always be

BBBBB

I've got most of it, but I can't figure out how to get rid of anything at the end of the line after EITHER the underscore OR the '@' (including either of those two characters).

Is this possible in one expression in sed? I can do it with piping the input through sed twice but I was wondering if one pass would do it. Currently I'm using

sed "s/^.*\/\(.*\)[_@].*$/\1/"

Which doesn't get rid of the "_ccc" when it appears, just the "@00000".

Suggestions?