? ????? ?? ??? ??????? ?????? ?????????? ????? ???? ??????? ??????? ????? ?? ????? ? ???? ???. ??????? ???? ??????, ??????} {?????? ?????? ?????? ????, ?????? ???????? ????? ?? ????? ? {???? ?????, ????? ????. ????? ???????: ????? ???????? ???? ?-21 ???? ?-21, ???? ????????? ????? ?????? ???????. ????? ?????????? ?????? ?? ???? ??????, ?????????z