import math

class Complex:
    def __init__(self, real, imaginary):
        self.re = real
        self.im = imaginary
    def __str__(self):
        return "{}+i{}".format(self.re, self.im)
    def __repr__(self):
        return "[Complex: re = {}, im = {}, length = {}]".format(
            self.re, self.im, self.norm() )
    def norm(self):
        return math.sqrt(self.re**2+self.im**2)
    def __eq__(self, other):
        return self.re == other.re and self.im == other.im
    def __ne__(self, other):
        return self.re != other.re or self.im != other.im
    def __lt__(self, other):
        return self.re < other.re and self.im < other.im
    def _my_secret_method(self, x):
        return Complex(x*self.re, x*self.im)
        
class Example:
    exists = False
    number = 0
    def __init__(self, x, y):
        self.radius = math.sqrt(x*x+y+y)
        self.x = x
        self.y = y
        Example.exists = True
        Example.number += 1
    def __str__(self):
        return "Example: radius {}, x {}, y {}".format(
            self.radius, self.x, self.y)