<gh_stars>10-100
class Solution:
    def isPowerOfFour(self, num: int) -> bool:
        return num > 0 and num&(num - 1) == 0 and (num - 1)%3 == 0

class Solution:
    def isPowerOfFour(self, num: int) -> bool:
        return num > 0 and num&(num - 1) == 0 and (num - 1)%3 == 0