using System;

public class Program

{

    public static void Main()

    {

        //Console.WriteLine(AireRectangle(21,29.7));

        //Console.WriteLine(Max(42, -33));

        //int a=25;

        //Console.WriteLine(Max(a, 27));

        //Console.WriteLine(Max3(-18.5, a, 100));

        Console.WriteLine(Absolue(1));

    }

    public static double AireRectangle(double longueur, double largeur)

    {

        return longueur*largeur;

    }

    public static double Max(double n1, double n2)

    {

        if (n1<n2)

        {

            return n2;

        }

    else

        {

        return n1;

        }

    }

    public static double Max3(double a, double b, double c)

    {

        return Max(Max(a,b),c); 

    }

    public static int Absolue(int a)

    {

        if (a>=0)   

        {

            return a;

        }

        else

        {

            return ((-1)*a);

        }

    }

}