6.The objective of Sudoku is to fill a 9 × 9 grid with digits so that each column, each row, and each of the nine 3 × 3 sub-grids contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which typically has a unique solution. The game can be modified to be 4 × 4 grids with 4 of 2× 2 regions containing number 1 to 4, 16x16 grids with 16 of 4x4 regions containing numbers 1 to 16, or 25x25 grids with 25 of 5x5 regions containing number 1 to 25 etc. For a Sudoku problem nn × nn grids with nn of √n × √n regions containing numbers 1 to n. design a simple brute-force algorithm for the Sudoku problem with k squares on the board already filled with numbers first. What is the complexity of your algorithm? Ans6.# A Backtracking program in Python to solve Sudoku problem