public class Complex {
    public final double real;
    public final double imag;

    public Complex() {
        this(0, 0);
    }

    public Complex(double r, double i) {
        real = r;
        imag = i;
    }

    public Complex add(Complex b) {
        return new Complex(this.real + b.real, this.imag + b.imag);
    }

    public Complex mult(Complex b) {