complex

class Complex:
    def __init__(self, real, imag):
        self.real = real
        self.imag = imag
    def __str__(self):
        sign = '+' if self.imag >= 0 else ''
        if self.imag == 0:
            return '{}'.format(self.real)
        else:
            return '{:.3f}{}{:.3f}i'.format(self.real, sign, self.imag)
class Calc:
    def add(self, c1, c2):  # сложение
        real = c1.real + c2.real
        imag = c1.imag + c2.imag
        return Complex(real, imag)
    def sub(self, c1, c2):  # вычитание
        real = c1.real - c2.real
        imag = c1.imag - c2.imag
        return Complex(real, imag)
    def mul(self, c1, c2):  # умножение
        real = c1.real * c2.real - c1.imag * c2.imag
        imag = c1.imag * c2.real + c1.real * c2.imag
        return Complex(real, imag)
    def cdiv(self, c1, c2):  # деление
        real = (c1.real * c2.real + c1.imag * c2.imag) / ((c2.real ** 2) + (c2.imag ** 2))
        imag = (c2.real * c1.imag - c1.real * c2.imag) / ((c2.real ** 2) + (c2.imag ** 2))
        return Complex(real, imag)
    def abs(self, c):
        return (c.real ** 2 + c.imag ** 2) ** 0.5