????? ???????? ??????? ???? ????? ???????? ?????? ???? ???? ?? ????? ???????? ?????? ???? ??? ???? ??? ?????? ?? ????? ??? ???????? ?? ??? ??????? ??? ????? ???? ????? ???? ??????? ?????????? ???????? ????????.????? ???????? ?????????- ??? ???????? ????????? ???????? ??: ?????? = ?????????? ????? + ???? ??????? (?? ???? ?????????). ???? ???????? ??