What does this mean?

Question

https://code.sololearn.com/cO9nW5WjZ7Bt/?ref=app
Can you explain the error?

Answer 1

When you are running programs in those playgrounds, you will send your input to a server, which has your code.
Then the runs the program with the input in the server and returns the output to your device.

Sololearn don't want clients to do changes on their systems, that's why you are not able to use command prompt.