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 man with green glasses does a trick on his skateboard.
Hypothesis: A man is good on his skateboard.
Update: He is holding the skateboard with his feet.
strengthener

Premise: A bearded man plays an instrument in front of a stone wall.
Hypothesis: The instrument is a tuba.
Update: The instrument is large and made of brass.
strengthener

Premise: A boy pets a sleeping tiger while another tiger sleeps behind him.
Hypothesis: A boy pets a tiger, while another tiger pretends to sleep.
Update: The tiger's tail is twitching back and forth

strengthener