How to avoid pagebreak using input?

Question

I'm just starting to use TeX, and I'm having a lot of trouble with it, which is why I'm asking.

I am creating a solution of Lang Algebra for my personal collection. Since there are a lot of exercises, I think it is essential to save them in separate files, so I started to separate them and write them in TeX.

I know how to concatenate TeX files using input, but I'm getting unnecessary pagebreaks and would like some help.

I currently write my files this way:

Main
ㄴMain of Chapter 1
　ㄴChapter 1, section 1
　ㄴChapter 1, section 2
　ㄴChapter 1, section 3
...

And Main of Chapter 1 is just like this.

\chapter{Chapter 1}
\include{Ch01/ch01_1}
\include{Ch01/ch01_2}
\include{Ch01/ch01_3}

This is creating unnecessary page transitions like below. What can I do to fix this? Please let me know!

This is what I want.

But it's outputting like this