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".

The problem knows easily.
unacceptable

The boy whose guardian's we elected employer president betrayed us.
unacceptable

he belief that Mary kissed Bill is mistaken.

unacceptable