TriangleArea

using System;

class TriangleArea
{
    static void Main(string[] args)
    {
        double a = double.Parse(Console.ReadLine());
        double h = double.Parse(Console.ReadLine());
        double area = a * h / 2;
        Math.Round(area, 2);
        Console.WriteLine("Triangle area = {0:F2}", area);
    }
}