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".
--------
Question: The harder it rains, how much faster a flow do you see in the river?

Answer: acceptable


Question: Nixon's behavior gave an idea for a book to every journalist living in New York.

Answer: acceptable


Question: I believe that the problem is not easy to be obvious.

Answer:
unacceptable