using System;

public class Program

{

    public static void Main()

    {

        double x, D;

        double a = double.Parse (Console.ReadLine());

        double b = double. Parse (Console.ReadLine());

        double c = double.Parse (Console.ReadLine());

        double d = double.Parse (Console.ReadLine());

        if (a==0)

        { x = -c*-b;

         Console.WriteLine(x);}

        else

        {D =  b*b-4*a*c;

         if (D<0)

         {Console.WriteLine("Няма решение");}

         {x = -b/2*a;

          Console.WriteLine (x);}

         {D = b*b-4*a*c;} 

         if (D==0)

         {Console.WriteLine("Има едно реше x1 = {0}");}

          if (D>0)

          {Console.WriteLine("Има две решения x1={0} , x2={1}", (-b+d)/2*a, (-b-d)/2*a);}

        Console.WriteLine("Hello World");

    }

}