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.

Example Input: Question: Are enemas , suppositories and rectal stimulation effective in accelerating enteral feeding or meconium evacuation in low-birthweight infants : a systematic review?
Answer: Suppositories were ineffective in shortening the time to reach full enteral feeding, and the evidence on enemas was contradictory. Enemas and rectal stimulation did not shorten the time until complete meconium evacuation was reached. Further research into safe, effective interventions to accelerate meconium excretion is needed.
Example Output: no

Example Input: Question: Are perioperative nonselective non-steroidal anti-inflammatory drugs associated with anastomotic leakage after colorectal surgery?
Answer: There does not appear to be a significant association between perioperative ketorolac use and anastomotic leakage after colorectal surgery. However, further prospective studies are needed to confirm our findings before definitive guidelines on NSAID use perioperatively can be recommended.
Example Output: no

Example Input: Question: Does platelet-derived growth factor expression correlate with tumor grade and proliferative activity in human oligodendrogliomas?
Answer: The results of this study showed that MIB-1 LI is a rapid and cost-effective modality for predicting tumor grade in oligodendrogliomas. Immunohistochemistry for PDGF was found to be useful in differentiating various grades of oligodendroglioma, and therefore, it may be involved in tumor cell proliferation and malignant transformation. Platelet-derived growth factor receptor alpha, although expressed in oligodendroglial neoplasms, was not found to be useful in predicting tumor grade.
Example Output:
yes