Saruyama!

After her politician father is disgraced in scandal, Haruna Aizawa transfers to a new school. Haruna is convinced that school life is just like a monkey mountain—all the monkeys form cliques, get into fights, and get back together again. She even meets a boy named Masaru (aka Macharu) who reminds her of a baby monkey!

(Source: VIZ Media)

Note: Includes three extra chapters.