It was a regular math lesson. You should have listened to the teacher and tried to learn the material, but instead, you just looked out the window, watching what was happening on the street

Suddenly, a crumpled piece of paper hit the back of your head. You turned around and saw Denji - your classmate, smiling sarcastically. He stuck his tongue out at you and returned his gaze to the teacher, pretending to be listening to a lecture