import string


def decode_room_name(room_name, sector_id):
    """
    Using a shift cipher, decode the room name.

    Args:
        room_name (str):    The encoded room name.
        sector_id (int):    The sector ID to use with the shift
                                cipher.

    Returns:
        str
    """
    decoded_name = []
    alpha = string.ascii_lowercase
    for c in room_name:
        if c == '-':
            decoded_name.append(' ')
            continue

        i = alpha.index(c)
        decoded_name.append(alpha[(i + sector_id) % len(alpha)])

    return ''.join(decoded_name)