???? ????? ?????? ??? ??? ??? ???? ??, ???????? ?? ?? ??? ?? ???? ???? ????. ?? ????? ???? ?????? ??? ???? ?? ???, ???? ?? ??? ???? ??? ??? ??? ?? ??? ?????.It is widespread practice to mark possible values for cells within the cell corners until finally all but 1 are actually tested impossible; for specifically demanding puzzles, sometimes total r