Print the input yourself: https://docs.codewars.com/training/troubleshooting/#print-input

For one kind of boxes the printer has to use colors which, for the sake of simplicity, are named with letters from a to m.

Your code is wrong. Not a kata issue.

Take a look at this: https://docs.codewars.com/getting-started/solving-kata and this: https://docs.codewars.com/training/troubleshooting then, it'll be useful.

Then look at other solutions in Solutions section, you can see there if there are better solutions than yours.