???? ?? ??? ????? ?? ??? ???? ????? ?? ????? ???? ?? ?? ??? ??? ????? ?? ?????? ??????? ????? ????? ??????? ??? ???? ???? ???? ?????? ?? ????? ?????? ???? ????? ???? ??? ???? ????????? ??? ??? ??? ?????????? ???? ?? ???? ???? ???? ??? ????? ?? ???????? ????? ????, ???? ???? ???? ???? ????? ???? ???? ??????? ???????? ? ???????????? ?????? ?) Suppose