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.
You should start by printing the input to console.
Your task is to count characters that occur more than once, but you are only counting the ones that occur even number of times.