using System;

public class Program

{

    public static void Main(string[] args)  

    {

    Console.Write(" a = ");

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

    Console.Write(" b = ");

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

    Console.Write(" c = ");

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

    double delta = b*b - 4*a*c ;

    if ( a==0 )

    {

        Console.WriteLine(" Phuong trinh nhap vao khong phai la phuong trinh bac 2 ");

    }

    else if (delta < 0)

    {

        Console.WriteLine("Phuong trinh vo nghiem");

    }

    else if ( delta == 0)

    {

        Console.WriteLine("Phuong trinh co 2 nghiem x1 = x2 = {0} ", -b/(2*a)) ;

    }

    else

    {

        Console.WriteLine("Phuong trinh co 2 nghiem phan biet x1,x2 ");

        double x1= (-b + Math.Sqrt(delta))/(2*a);

        double x2= (-b - Math.Sqrt(delta))/(2*a);

        Console.WriteLine("- x1 = {0} ", x1);

        Console.WriteLine("- x2 = {0} ", x2);

    }

    }

}