# Given an integer(signed 32 bits), write a function to check whether it
# is a power of 4.

# Example:
# Given num = 16, return true. Given num = 5, return false.

# Follow up:
#     Could you solve it without loops / recursion?


class Solution(object):

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