???? ??? ????? ?????? ?????????? ?????? ???? ????? ??????. ???/??/??? ????? ???????? ????? ???????, ? ????? ????? ???????/demand and supply ??? ????? ??????/????. ??? ??????? ??? ?????/???????/?????? /???? ????? ?/among ??????????/???????/???????. ????? /???? /??? ??????? ??????? ?????? /????????? ??/????? ????????? ?? ?????/???????? ?? ????