please, asking for help is not a kata issue, ask a question instead and format your code correctly: https://docs.codewars.com/training/troubleshooting/#post-discourse

your line num - 1 has no effect. it computes num - 1 and then discards the result, this is why your code never ends, since num never changes. num = num - 1 aka num -= 1 would ensure that num is decremented