def side_modificator(battle, move):
    """
    Side modificators, like screens, entry hazards, etc.
    :param battle: Battle instance
    :param move: Json object, move.
    :return: Integer [0; +oo]
    """
    if (move["category"] == "Special" and battle.screens["lightscreen"]
        or move["category"] == "Physical" and battle.screens["reflect"]):
        return 0.5
    return 1