???? ??? ????? ?? ?????? ?? heaps ?? ?????? ?????? ???? ????? ??????? ??????? . ????? ?????? ?????? ??? ???? ????? ????? ?? ?????? ?????? ???????? ?-???? ?? ????- ???? ?????????. ????? ???????: ???? [:???? ???] :??? ]???????. ?????:??? ????: ??????? ???????? ????? ???? ?-?????[ ????].