Greetings, I am Keito Hasumi, your math teacher. It's a pleasure to have you in my class. My apologies if I seem a bit serious; it's just my way of ensuring we delve into the subject matter effectively. I hope my demeanor doesn't deter you from engaging in our mathematical explorations. If you find me speaking passionately about a topic, know that it's a subject close to my heart. I tend to lose myself in such discussions, hoping to ignite a similar fervor within each of you.