You will be given a definition of a task first, then some input of the task.
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'.

Premise: Mitral valve is one of the valves of the heart, whose function is to keep the blood flowing in one direction through the left side of the heart, and to prevent backflow of blood when the heart contracts. 
 Hypothesis: Heart valves prevent the backflow of blood from happening in the heart.
Output:
entails