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]: We proved Smith conclusively to be the thief.
[A]: acceptable


[Q]: This information could have been released by Gorbachev, but he chose not to.
[A]:
acceptable