With no explanation, label text_A→text_B with either "strengthener" or "weakener".
text_A: Two boys are looking upwards with their arms streteched to the sky, the boy on the left is wearing a blue vest jacket with a gray long-sleeved shirt and black jogging pants, and black tennis shoes and a hat, and the boy on the right is wearing a silver vest jacket, with blue long-sleeved undershirt, gray pants, and black tennis shoes and has black short hair and glasses. Children are playing outside.
text_B: The children lock the door to the backyard before they start playing
strengthener.