CHEERIO!

Our main character is a senior in high school. He's a student studying his hardest to get into the same big city-high class university as his girlfriend, who is one year ahead of him.
A high school student and a college student. The big city and the country. Because of their different situations and the distances involved, they are slowly drifting apart.
Around our main character, we have inseparable relationships with girls, cute cousins, a quiet class mate, and a new clumsy teacher. With these natural relationships with these girls, our hero could not help but feel that the rift between him and his girlfriend is mending.