using System;

public class Program

{

    public static void Main()

    {

        var a = double.Parse(Console.ReadLine()); 

​

        var h = double.Parse(Console.ReadLine()); 

​

        var area1 = (a * h) / 2; 

​

        var area = Math.Round(area1, 2); 

​

        Console.WriteLine("Triangle area = " + area); 

    }

}