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".

John knows whose book Mary bought and Tom talked.
unacceptable

The man who ordered ice cream said the pudding would be tasty.
acceptable

John is likely to be kept on participants.

unacceptable