Help me find this masterpiece

Bl. Two guy in high school trying to finish their exam. The red head just transfer to the school and sit next to the ml. Ml is from a mafia family. Ml teach red head for finals. Red head is very bed at studying so his grades aren't that good eventhough ml teach him every week. The story is very short (about 15 chapters i think) and the end makes you wanting more. Pls help!! ╥﹏╥