using System;

public class Program

{

    public static void Main()

    {

        double a,b;

        Console.WriteLine("enter hight 1 im meters:");

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

        Console.WriteLine("enter hight 2 in meters:");

        b= double.Parse(Console.ReadLine());

        Console.WriteLine("the hight defrens is:" + (Math.Abs(a) - Math.Abs(b)));

    }

}