Given the task definition, example input & output, solve the new input case.
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'.
Example: Premise: Lyme Disease is caused by a bacterium that's transmitted by tick bite, but many infected people don't remember a bite. 
 Hypothesis: Lyme disease is caused by bacteria.
Output: entails
The premise sentence agrees with the hypothesis that Lyme Disease is a bacterium. The premise also gives additional information about Lyme disease. Therefore Premise entails Hypothesis.

New input case for you: 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