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: Is unexplained elevated maternal serum alpha-fetoprotein predictive of adverse perinatal outcome in an indigent urban population?
Answer: Elevated maternal serum alpha-fetoprotein levels offer little if any additional predictive value for adverse perinatal outcome in populations already at high risk for such outcomes on the basis of obstetric or socioeconomic criteria.

Ex Output:
no


Ex Input:
Question: Is apoptosis inhibitor-5 overexpression associated with tumor progression and poor prognosis in patients with cervical cancer?
Answer: API5 expression is associated with pERK1/2 in a subset of cervical cancer patients and its expression predicts poor overall survival, supporting that API5 may be a promising novel target for therapeutic interventions.

Ex Output:
yes


Ex Input:
Question: Is knee arthroscopic surgery beneficial to middle-aged patients with meniscal symptoms : a prospective , randomised , single-blinded study?
Answer: Middle-aged patients with meniscal symptoms may benefit from arthroscopic surgery in addition to a structured exercise programme. Patients' age or symptom history (i.e., mechanical symptoms or acute onset of symptoms) didn't affect the outcome.

Ex Output:

yes