Given an integer n, return true if it is a power of two. Otherwise, return false.

An integer n is a power of two if there exists an integer x such that n == 2^x.

Example 1:

Input: n = 1
Output: true (2^0 = 1)

Example 2:

Input: n = 16
Output: true (2^4 = 16)

Example 3:

Input: n = 3
Output: false

Constraints: -2^31 <= n <= 2^31 - 1