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".

[Q]: Have in our class the kids arrived safely?
[A]: unacceptable


[Q]: The students looked the high stairs up.
[A]: unacceptable


[Q]: Mary would solve the problem.
[A]:
acceptable