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:
He never achieved anything, didn't he?

Ex Output:
unacceptable


Ex Input:
An oak tree will grow from that acorn.

Ex Output:
acceptable


Ex Input:
Calvin will eat.

Ex Output:

acceptable