using System;

public class Operation
{
    public static double TriangleArea(double a, double b, double c)
    {
        double p = (a + b + c) / 2;
        bool exists = CheckTriangle(a, b, c);
        if (!exists)
            return -1;

        return Math.Sqrt(p * (p - a) * (p - b) * (p - c));
    }

    public static double TriangleArea(double a)
    {
        return TriangleArea(a, a, a);
    }


    public static bool CheckTriangle(double a, double b, double c)
    {
        if (a <= 0 || b <= 0 || c <= 0) return false;

        double maxSide = Math.Max(Math.Max(a, b), Math.Max(b, c));

        if (maxSide >= a + b + c - maxSide) return false;

        return true;
    }

    public static int SolveQuadratic(int a, int b, int c, out double x1, out double x2)
    {
        double d = b * b - 4 * a * c;
        if (d > 0)
        {
            x1 = (-b + Math.Sqrt(d)) / (2 * a);
            x2 = (-b - Math.Sqrt(d)) / (2 * a);
            return 1;
        }
        else if (d == 0)
        {
            x1 = x2 = -b / (2 * a);
            return 0;
        }
        else
        {
            x1 = x2 = -1;
            return -1;
        }
    }

}