public class Lettre extends Courrier{
	private boolean urgent;

	public Lettre(boolean u){
		super(1.0);
		urgent = u;
	}
	public Lettre(){this(false);}
	public double affranchir(){
		if (urgent) return 0.8;
		else return 0.5;
	}
	public String toString(){
		if (urgent) return "Lettre urgente";
		else return "Lettre ordinaire";
	}
}