Detailed Instructions: You are given two sentences. You have to find if there is entailment or agreement of the Hypothesis by the Premise. From the given pair of sentences, you should identify if there is enough information in the Premise to support the claim made in the Hypothesis. The Premise may not exactly be the same as Hypothesis. Your task is to return 'entails' if the premise supports hypothesis else return 'neutral'.
Q: Premise: The presence of valves in the veins prevents the backflow of blood once drawn toward the heart. 
 Hypothesis: Heart valves prevent the backflow of blood from happening in the heart.
A:
entails