using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("please enter student's high");

        double s1 = double.Parse(Console.ReadLine());

        Console.WriteLine("please enter student's high");

        double s2 = double.Parse(Console.ReadLine());

        double sub = Math.Abs(s1 - s2);

        Console.WriteLine("the sub high is: " + sub);

    }

}