�
??????:
??? ??? ???? ???
2/3 ??? ???
2 ???? ???? ???'??
4 ???? ??? ???
4 ???? ??? ??????
???
???? ???? ????
??? ????? ???? ??????? ?????? ??
???? ?????:
1. ????? ?? ????? ????? ??????? ?? ?????? ???? ??????.
2. ????? ?? ???? ?????