using System;

public class Program

{

    public static double EX51 (double surface)

    {

        double cote = Math.Sqrt(surface);

        return cote;

    }

    public static void EX52 ()

    {

        Console.WriteLine("Veuillez saisir la surface du carré");

        double surface = Convert.ToDouble(Console.ReadLine());

        double cote = EX51 (surface);

        Console.WriteLine("La surface du carré est " + cote);   

    }

    public static void Main()

    {

        EX52 ();

    }

}