You're given a sentence and your task is to classify whether the sentence is acceptable or not. Any sentence which is grammatically correct, has a naturalistic text, is written by a native speaker and which minimizes superfluous content is acceptable, otherwise unacceptable. If the sentence is acceptable then write "acceptable", otherwise "unacceptable".

Sally started running down the street, but only after José started.
unacceptable

Bob proved that this set is recursive.
acceptable

Susan whispered the news to Rachel.

acceptable