Definition: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) the answer is unique, (iv) its answer is a continous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage 
Input: John was in the third grade, and nine years old. Every day he had to walk home from school. There were some kids in his class who were mean to him, and during the winter they would throw snowballs at him. John could have told the teacher, but one of the kids was a very pretty girl. She was mean, but John liked her because she was pretty and did not want her to get in trouble. 

One day, his teacher asked John to stay after class to wipe off the chalkboard and to empty the pencil sharpener. By the time he was done, the other kids had gone home. They could no longer throw snowballs at him. John did not mind helping out his teacher, and he soon stayed after class every day. 

John was not very good at math, and sometimes his teacher would help him when he stayed after school. She said if John could help her out for at least two weeks, he could pass his math class. John thought it was a good deal, and ended up being much better at math.
Output:
What did kids do to John?