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]: I saw him leaving the main building.
[A]: acceptable


[Q]: The cook boned the fish of bones.
[A]: unacceptable


[Q]: In preparation for the return fixture this team has trained more efficiently than they had in recent months.
[A]:
acceptable