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: Consider Input: Question: Does degenerative spondylolisthesis affect the outcome of unilateral laminotomy with bilateral decompression in patients with lumbar stenosis?
Answer: Our study thus indicates that preoperative degenerative spondylolisthesis does not worsen the outcome of patients with lumbar stenosis undergoing unilateral laminotomy with bilateral decompression. These results suggest that lumbar fusion is often unnecessary in patients with degenerative spondylolisthesis and lumbar stenosis if the posterior decompression technique is unilateral laminotomy with bilateral decompression.

Output: no


Input: Consider Input: Question: Are arterial stiffness and pulse wave reflection increased in patients suffering from severe periodontitis?
Answer: The results of this study confirm the association between periodontal inflammation and increased cardiovascular risk shown by impaired vascular health in case of severe periodontitis. As impaired vascular health is a common finding in patients suffering from severe periodontal disease a concomitant routine cardiovascular evaluation may be advised.

Output: yes


Input: Consider Input: Question: Is perioperative screening for metastatic disease indicated in patients with primary breast cancer and no clinical signs of tumor spread?
Answer: In breast cancer patients without clinical signs of tumor spread perioperative screening for metastases is not warranted because of low frequency of metastases, false positive findings, missing therapeutic consequences and high costs.


Output: no