public Piece.TypePiece askPromotion(ChessGame G){
		String L = null;
		Piece.TypePiece type = Piece.TypePiece.P;
		System.out.println("Write the piece you want(one character) :");
		System.out.println("\"P\" : Pawn");
		System.out.println("\"B\" : Bishop");
		System.out.println("\"N\" : Knight");
		System.out.println("\"R\" : Rook");
		System.out.println("\"Q\" : Queen");
		boolean ok = true;
		do {
			while(((L=sc.nextLine()).length())!=1)
			{
				System.out.println("Error.\nTry again.");
			}
			switch (L) {
				default : ok = false;
					break;
				case "P" : type = Piece.TypePiece.P;
					break;
				//Bw or Bb will do
				case "B" : type = Piece.TypePiece.Bb;
					break;
				case "N" : type = Piece.TypePiece.Kn;
					break;
				case "R" : type = Piece.TypePiece.R;
					break;
				case "Q" : type = Piece.TypePiece.Q;
					break;
			}
		}while (!ok); 
		return type;
	}