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".
--------
Question: Willy is taller than Bill by as much as I know a boy who thinks that Bill is taller than Dan.

Answer: unacceptable


Question: He established his innocence with the letter.

Answer: acceptable


Question: Where did the policeman meet several young students?

Answer:
acceptable