Can anyone explain me the logic of this code?

Question

I cannot understand why this code outputs:
1
2
3
Can anyone explain me please 🤔
https://code.sololearn.com/cB45sc5BQyBI/?ref=app

Answer 1

I still not properly understand but get a bit of this, thanks a lot David for helping me out 😊
Recursion is really difficult.

Answer 2

Output
2
3

Answer 3

It follows condition showing here