Hiatari Ryoukou!(1979)

Hiatari Ryoukou!

The story focuses on the relationships of Kasumi Kishimoto, a high school student. When she enters Myoujou High School, she moves into her aunt's boarding house, where four boys attending the high school are tenants. Despite her steadfast determination to stay loyal to her boyfriend, who is studying abroad, Kasumi finds herself slowly falling in love with one of the boarders, Yuusaku.

(Source: Wikipedia)