Sudoku is a puzzle consisting of a 9x9 board divided into nine 3x3 subboards. In a typical puzzle, several of the squares are already filled, as in the example shown below. The goal of the puzzle is to place the numerals 1 through 9 into the remaining squares of the board in such a way that no numeral is repeated in any row or column or 3x3 subboard. Use the non-Boolean model technique to solve this puzzle.