{
    internal class Program
    {
        static void Main(string[] args)
        {
            double a = Convert.ToDouble(Console.ReadLine());
            double b = Convert.ToDouble(Console.ReadLine());

            if (a >= b)
                return;

            double h = (b - a) / 10;

            double FinalS = S(a, b, h, 0);
            double Y(double x)
            {
                return Math.Sin(x);
            }

            double S(double a, double b, double h, double S_Last)
            {
                double epsilon = 0.0001;
                double s = 0;
                double x = a;
                while (x < b)
                {
                    double y1 = Y(x);
                    double y2 = Y(x + h);
                    double dx = h;
                    s += dx * (y1 + y2) / 2;
                    x += h;
                }
                if (S_Last == 0 || Math.Abs(s - S_Last) > epsilon)
                {
                    return S(a, b, h / 2, s);
                }
                else
                    return s;
            }
            Console.WriteLine(FinalS.ToString());
        }

    }
}