LC263. Ugly Number

class Solution:
    def isUgly(self, num: int) -> bool:
    # step1:  edge case -  num <= 0   
        if num <= 0: return False
    # step2:  strip num with all candidate prime factors until num reach mininum 
        while num % 2 == 0:
            num = num//2 
        while num % 3 == 0:
            num = num//3
        while num % 5 == 0:
            num = num//5
    # true condition: check if num == 1 
        return num == 1