TASK DEFINITION: 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.
PROBLEM: Premise: Middle-age students sitting in rows of tables listening to a teacher sitting in front of room behind desk.
Hypothesis: The teacher is teaching the students about classic literature.
Update: Math problems are written on the chalkboard.

SOLUTION: weakener

PROBLEM: Premise: A man is swinging on a rope above the water.
Hypothesis: A man pretends to be Tarzan as he swings around.
Update: The man holds the rope with two hands.

SOLUTION: weakener

PROBLEM: Premise: A man is performing acrobatics over a group of people kneeling on the ground.
Hypothesis: The acrobat is doing a hard trick.
Update: The acrobat is concentrating very intently.

SOLUTION:
strengthener