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 renal excretion of fluoride after fluoride mouth rinse in children?
Answer: After the use of a fluoride mouthwash, in children, there is a statistically significant increase of fluoride ion in urine, which can be attributed to the application of this product.

Ex Output:
yes

Ex Input:
Question: Does a novel biomechanical device improve gait pattern in patient with chronic nonspecific low back pain?
Answer: Patients with NSLBP treated with the novel biomechanical device for 3 months increased walking speed through longer step length and eliminated asymmetrical differences.

Ex Output:
yes

Ex Input:
Question: Does portal venous stasis during liver resection affect platelet aggregability?
Answer: Induced platelet aggregability is not affected by the method of surgical bleeding control used in liver resection. Platelet aggregability seems to be resistant even to portal venous stasis of up to 50 min during Pringle manoeuvre.

Ex Output:
no