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".

Ex Input:
The harder it rains, how much faster a flow do you see in the river?

Ex Output:
acceptable


Ex Input:
Bob proved that this set is recursive.

Ex Output:
acceptable


Ex Input:
Stephen persuaded Ben to be careful.

Ex Output:

acceptable