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.

Ex Input:
Question: Does the rtPA increase MMP-9 activity in serum during ischaemic stroke?
Answer: Thrombolysis applied for IS treatment increases MMP-9 activity in serum, however, rtPA does not facilitate the conversion of pro-MMP-9 into the active form. Our results also suggest the involvement of MMP-3 to the biochemical processes occurring during acute phase of IS.

Ex Output:
yes

Ex Input:
Question: Does short-term , high-dose glucocorticoid treatment contribute to reduced bone mineral density in patients with multiple sclerosis?
Answer: Reduced BMD was prevalent in patients with MS. GC treatment appears not to be the primary underlying cause of secondary osteoporosis in MS patients.

Ex Output:
no

Ex Input:
Question: Does high expression of vascular endothelial growth factor in EV71-infected patients originate from EV71-infected cells?
Answer: Our data reveal that EV71 infection of four human cell lines induced VEGF mRNA expression but did not induce VEGF protein expression in the infected cells. Therefore, the increased VEGF protein expression in EV71-infected patients may be due to the influence of surrounding non-infected cells following stimulation of proinflammatory cytokines secreted from the infected cells.

Ex Output:
no