Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Try to recreate the problem in our IDE. See here to find out what input causes it to fail, and see if the same input works in your IDE.
Did you return or print the result?