CalculateTiangleArea

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;



namespace ConsoleApp1
{
    class Program
    {


        static void Main()
        {
            double width=double.Parse(Console.ReadLine());
            double height = double.Parse(Console.ReadLine());
            double area = GetTriangleArea(width,height);
            Console.WriteLine(area);
        }

        static double GetTriangleArea( double width, double height)
        {
           return width * height / 2;

        }


    }
}