def isPowerOfTwo(n: int) -> bool:
    return n > 0 and (n & (n - 1)) == 0
test_cases = {
    1: isPowerOfTwo(1),    
    16: isPowerOfTwo(16),    
    3: isPowerOfTwo(3),     
    64: isPowerOfTwo(64),    
    0: isPowerOfTwo(0),      
    -4: isPowerOfTwo(-4)     
}
for n, result in test_cases.items():
    print(f"Input: {n}, Output: {result}")