So, I have read through the issues section on this Kata, so it would be pointless for me to bring up the same things so many others have brought up because it doesn't seem to be making any sense to the individuals in charge of change with this kata. So instead, I'll try this way. In the kata description there is no way to know to what extent the program needs to run the product. What I mean is that there is no statement of "Your code needs to be able to run x number of digits in the input." It would help prepare people to know they need to be efficient rather than having it sprung on them after working hard to come up with a solution. I hope this helps, and thank you for this kata. It was a lot of fun to work on.