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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.
The problem description misses a huge amount of info about the problem. Reading the description along will not give you sufficient knowlege about the problem to pass all the test cases.