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.

Premise: A young man goes air-born while his skateboard spins underneath him.
Hypothesis: The man is not wearing a helmet.
Update: His hair is flying in front of his face.
strengthener

Premise: A man in a baseball cap playing a black acoustic guitar.
Hypothesis: A male musician in a baseball cap playing on his black acoustic guitar as other give him money on a street corner.
Update: Passersby clapped enthusiastically as the music continued and then placed dollar bills in his open guitar case on the sidewalk.
strengthener

Premise: A man wearing a big white hat and a logo t-shirt is playing guitar and singing.
Hypothesis: A man is playing instrument.
Update: People are looking up at the man and cheering.

strengthener