With no explanation, label text_A→text_B with either "strengthener" or "weakener".
text_A: Two men in karate uniforms, one with red gloves and belt and the other with blue gloves and belt, box, while the man in blue is making a face as if her were screaming. The karate instructor is annoyed with his students.
text_B: The instructor shakes his head with their poor performance
strengthener.