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.
There is no test expecting NaN. It seems your function is returning NaN instead of 6. Print the input: https://docs.codewars.com/training/troubleshooting#print-input see why your code is failing.