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.
What is the purpose of including units if they're only used for the output message?
Also, this
n < 0,n == 0cases handling feels like stretching the kata because you couldn't think of anything except "find maximum area, knowing shape perimeter".