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.

Example Input: Premise: A flying machine with a yellow sail is landing with industrial buildings in the background.
Hypothesis: The machine is not gas-operated.
Update: The machine has a battery.
Example Output: strengthener

Example Input: Premise: A man and women dance together while a crowd looks on on a wooden surface.
Hypothesis: some people's are watching the dance performance made by a man and women
Update: The couple are dancing on the wooden surface.
Example Output: strengthener

Example Input: Premise: A dog jumps and catches a Frisbee in the grass.
Hypothesis: The frisbee is purple.
Update: The frisbee is the color of a grape.
Example Output:
strengthener