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: Does helicobacter pylori infection in Mongolian gerbils initiate hematological diseases?
Answer: A single H. pylori infection is insufficient to cause onset of ITP or IDA and other factors may be required for disease onset.
Example Output: no

Example Input: Question: Is the relationship between insomnia with short sleep duration associated with hypercholesterolemia : a cross-sectional study?
Answer: Insomnia with short sleep duration was associated with increased odds of hypercholesterolemia. Caregivers in clinical practice should watch out for the effect brought by this novel factor.
Example Output: yes

Example Input: Question: Does hIV Nef protein cause endothelial dysfunction in porcine pulmonary arteries and human pulmonary artery endothelial cells?
Answer: HIV Nef protein significantly decreases endothelium-dependent vasorelaxation in porcine pulmonary arteries. It also reduces eNOS expression and induces oxidative stress in both porcine pulmonary arteries and HPAECs. This study demonstrates a new mechanism of HIV Nef, which causes endothelial dysfunction and may contribute to the human pulmonary artery disease in HIV-infected patients.
Example Output:
yes