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: Are common genetic variants related to vitamin D status associated with esophageal squamous cell carcinoma risk in China?
Answer: Our results suggested that common genetic variants related to vitamin D levels are not associated with risk of ESCC in this Chinese population.

Ex Output:
no

Ex Input:
Question: Does interaction of programmed death-1 and programmed death-1 ligand-1 contribute to testicular immune privilege?
Answer: The constitutive expression of PD-L1 in the testis is an important mechanism underlying testicular immune privilege and long-term survival of intratesticular islet allografts.

Ex Output:
yes

Ex Input:
Question: Does vascular reconstruction play an important role in the treatment of pancreatic adenocarcinoma?
Answer: An aggressive approach for stage II pancreatic cancers with venous or arterial invasion can be performed with comparable results when it is executed by an experienced institution with skilled oncologic and vascular surgeons.

Ex Output:
yes