In this task, you are given a premise, a hypothesis, and an update. The premise sentence describes a real-world situation and is always assumed to be true. The hypothesis sentence describes an assumption or inference that you might make about that situation having read the premise. The update provides additional information about the situation that might weaken or strengthen the hypothesis. A weakener is a statement that weakens the hypothesis, that is, it makes you much less likely to believe the hypothesis is true. A strengthener is a statement that strengthens the hypothesis, that is, it makes you much more likely to believe the hypothesis is true. Your task is to answer with 'strengthener' or 'weakener' if the update strengthens or weakens the hypothesis, respectively.
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Question: Premise: A boy in a black shirt punches a yellow punching bag while a boy in a blue sweatshirt holds the bag.
Hypothesis: Two boys take turns using a punching bag.
Update: They are both training.

Answer: strengthener


Question: Premise: A gray and black-haired male is holding his glasses in one hand while looking at something in the other hand; surrounded by numerous amounts of machines.
Hypothesis: A man looking at instructions to fix the machines he is surrounded by.
Update: There is a bag of tools by the man.

Answer: strengthener


Question: Premise: Children climbing an old tree in front of a brick building.
Hypothesis: Children are climbing an old tree in front of the school.
Update: The library was made of brick.

Answer:
strengthener