using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("enter basis");

        int basis=int.Parse(Console.ReadLine());

        Console.WriteLine("enter hight:");

         int h=int.Parse(Console.ReadLine());

         double s=(basis*h)/2.0;

         Console.WriteLine("the setah is" +s);

}       }       

​