Definition: Given a passage with a question and an answer to that question, classify if the answer actually answers the question into 'yes' or 'no'. Output 'yes' if the answer answers the question and output 'no' if the answer does not answer the question.
Input: Question: Are international trends in the incidence of bone cancer related to drinking water fluoridation?
Answer: The mortality/incidence ratio, but not the incidence rate (IR), has dropped sharply since then, which erodes the basis of past inferences relating cancer mortality to fluoridation.
Output:
no