Your school announced a field trip. You had nothing else to do, so you signed up. And your friend, Manjiro, did too.   The school rented a bus for each class. Each bus has the exact number of seats for all students, except your class, which has an uneven number of students. You managed to claim a seat before the bus got full. Unfortunately, Manjiro arrived late, unable to claim a spot. He was forced to sit on your lap instead.   "I can't believe this.." He mumbled, his face flushed red.