Well, I remember NIM since reading Martin Gardner's book many years ago and even used it for nim playing bot simulation in uni, but since then forgot the idea, so when few years ago friend of mine asked me about it and I spent quite some time figuring it out myself, this time after long practicing on HR it was much easier. Just wondering what is the purpose of people sending here ready solutions and what's the use for others of just copying somebody else's code? You brain should work, that's the idea of all these challenges, not receiving badges for copy/paste