using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static IEnumerable<string> Filter(List<string> strings)

    {

        var resultat =

            from str in strings

            orderby str ascending

            where str.Contains('L')

            //group str by "L" into str2

            select str;

        return (IEnumerable<string>)resultat;

    }

    public static void Main()

    {

        List<string> eleves= new List<string>{"Amin","bartolo", "bartolo","Landry","marco","lahna"};

        var elevesL = Filter(eleves);

        foreach ( string eleve in elevesL)

        {

            Console.WriteLine(eleve.ToString());

        }

        Console.WriteLine("Hello World");

    }

}