???? significance ???????? ??????? ???. ??????? ???????? ??? ????? ??????? ?????? ??? ????? ?????? ????? ????? ?????????. ??? ????? ??? ????????? ? ??????? ???? . ?????? ???? ??? ????? ??????? ??? ??? ???????? ??????? ??? ??????? ???? ???? ?? ???? ????? ??????? ???????? ??????? ?????? ???? ? ?????? ???. ???? ??????? ???????, ????? ?????