def is_power_of_four(n):
   
    if n <= 0:
        return False

    
    log_base_4 = (n ** 0.5) ** 0.5  
    
    return log_base_4.is_integer()  


# Test Examples
print(is_power_of_four(16))
print(is_power_of_four(5))  
print(is_power_of_four(1))