And why do you downvote my answers explaining why you should use spoiler flag? You can simply see the homepage and realize that, I'm not saying it's obvious, hence, my posts explaining why. In fact I suggested the spoiler flag was marked by default in solutions or adding a placeholder, but it didn't happen so, the best I can do is tell the users that don't know how it works, what should be done.

@Chrono79 I have no idea how someone is supposed to know that replies/comments in the solution discussion are visible on the homepage. I just joined codewars and I had no idea it works like that if I didn't see your comment. I wouldn't have known I need to put a spoiler flag in a reply to the solution. If you want that to happen, there needs to be some announcement somewhere that comments posted here are visible on the homepage without a spoiler flag.

Absolutely beautiful solution, what do I have to look for if I want to learn cool number theory like this? My maths is pretty bad, but I love learning about these sort of things.

Your posts here are visible in the homepage discourse if you don't use it.

Seriously though, I'm curious about the running time of this solution

I can't think why that would be interesting, but what is stopping you from cut/paste and running it to see for yourself?

Please use spoiler flag next time.

That is the thing, we have to consider all the cornercases. As, programmers we must be prepared how users are going to use the software.

I know, right? I started working at NASA but I had to quit because they kept nagging about my code and saying stuff like "The rocket must not explode on re-entry" and "Fuel consumption must be calculated exactly and nost just estimated" and all kinds of pesky details like that, ugh! So annoying!