quadratic equation

using System;



class Program
{
    static void Main()
    {
        double a, b, c;
        a = double.Parse(Console.ReadLine());
        b = double.Parse(Console.ReadLine());
        c = double.Parse(Console.ReadLine());
        double D = b * b - 4 * a * c;
            double x, x1, x2;
            if (D > 0)
            {
                x2 = (-b + System.Math.Sqrt(D)) / (2 * a);
                x1 = (-b - System.Math.Sqrt(D)) / (2 * a);
                Console.WriteLine("x1={0}; x2={1}", x1, x2);
            }
            else if (D < 0)
            {
                Console.WriteLine("no real roots");
            }
            else
            {
                x = (-b + System.Math.Sqrt(D)) / (2 * a);
                Console.WriteLine("x1=x2={0}", x);
            }
        }
    }