Why my code work on code block but not on code playground. What code should i modify? Do i make mistake.

Question

this is my code
https://code.sololearn.com/c4Tae27x774D/?ref=app

Answer 1

It worked for me, I think. I just had to anticipate all inputs the code requires before running it, because of the weird way Sololearn deals with multiple inputs. So I entered
1
2
10
N
and bought two pencils for $2, and got $8 as change.

Answer 2

thanks. i'll give comment in my code about your sugestion so i will remember it.