???? ??? ??????? ???? ????? ??? ??? ???????? ??? ????? ?????????? ?? ????? ??????? ?????. ????? ????? ??? ?ficulties ???? ?? ?????? ? ??? ???? ?????? ???????. ?????? ?????? ????? ???? ????? ????????? ????? ?????????? ???? ???. ???? ????? ??? ???? ??????? ????? ?????????? ?? ?????? ?????. ????? ?????? ????? ??? ????? ?????? ????????? ?????????