B Group no Shounen

Protagonist Sakuragi Ryou was in the "A group" in middle school. At least until he got caught up some trouble and developed a reputation as a delinquent. Wanting to live a normal, peaceful life in high school he decides to do a reverse high school debut, aiming to be in the boring, middle-of-the-pack "B group". Above all else he doesn't want to stand out. But then one day he encounters the school idol, Fujimoto Erika, being harassed by delinquents and begrudgingly decides to help her out. She then starts to develop an interest in him, which is going to make his goal of not standing out tough...adapted from the novel of the same name