???? ????? ??????? ?? ?????? ?????? ???? ???? ??? ??????? ?? ???? ????? ??????. ????? ??? ??????? ??????? ???? ?????? ??? ???????. ???? ??????? ??????? ?????????. ????? ????? ?????? ?????? ??????. ???? ??????? ??????? ????? ???? ?? ???????. Picking ???? ????? ??????? ??? ????? ???? ?????? need to consider ??? ?????. First, ??? goal ??