package com.company;

import java.lang.Exception;

class CustomException extends Exception{
    public CustomException(String err){
        super(err);
    }
}

class Equation {
    float a, b = 0;
    public  Equation(float a, float b) {
        this.a = a;
        this.b = b;
    }

    public float Resolve() throws CustomException{
        if (a == 0 && b == 0){
            throw (new CustomException("solution tout R"));
        }
        else if (a == 0 || b == 0){
            throw (new CustomException("impossible"));
        }
        else{
            return (-(b/a));
        }

    }
}

public class Main {

    public static void main(String[] args) throws CustomException {
        Equation eq = new Equation(0,0);
        System.out.println(eq.Resolve());
    }
}