public void initialDice(){
		int nb_faces = 0;
		while(true){
			try {
				System.out.println("How many faces of dice do you want ?");
				sc = new Scanner (System.in);
				nb_faces = Integer.parseInt(sc.nextLine());
				if (nb_faces < 1 || nb_faces > 20) throw new NumberFormatException();
				break;
			} catch(NumberFormatException e) {
				System.out.println("You must indicate an int between 1 and 20 includes.");
			}
		}
		this.dice = new Dice(nb_faces);
	}