Manhwa search

Yo,I'm looking for a manhwa and I don't remember the title exactly. Basically, if I remember correctly, the MC enters a high school where some are tall and calisthenics/bodybuilders ( Intimidating, etc.) . And the MC thinks he's going to have the worst schooling of his life, but the guys are super nice to him and towards the end of class, they ask the MC to follow them and he enters a warehouse I think, or another place .And there, in the center is a boxing ring, and the guys from the high school are hitting each other to see who is the strongest or I don't remember what reason, but it's always respectful but the rule is that the fight only ends if one of the two is knocked out.