public class NKnights {
    public static void main(String[] args) {
        int n=3;
        boolean[][] board=new boolean[n][n];
        System.out.println(2*knight(board,0,0,3));
    }
    static int knight(boolean[][] board,int row,int col,int tar){
        if(tar==0){
            display(board);
            System.out.println();
            return 1;
        }
        int count=0;
        if(row==board.length-1 && col==board.length) {
            return 1;
        }
        if(col== board.length){
            count+= knight(board,row+1,0,tar);
            return 1;
        }
        if(isSafe(board,row,col)){
            board[row][col]=true;
            count+=knight(board,row,col+1,tar-1);
            board[row][col]=false;
        }

        count+=knight(board,row,col+1,tar);
        return count;
    }

    private static boolean isSafe(boolean[][] board, int row, int col) {
        if(isValid(board, row-2, col-1)){
            if(board[row-2][col-1]){
                return false;
            }
        }
        if(isValid(board, row-1, col-2)){
            if(board[row-1][col-2]){
                return false;
            }
        }
        if(isValid(board, row-2, col+1)){
            if(board[row-2][col+1]){
                return false;
            }
        }
        if(isValid(board, row-1, col+2)){
            if(board[row-1][col+2]){
                return false;
            }
        }
        return true;
    }
    // TO CHECK THE BOUNDARIES OF ROWS AND COLUMNS
    static boolean isValid(boolean[][] board,int row,int col){
        if(row>=0 && row<board.length && col>=0 && col<board.length){
            return true;
        }
        return false;
    }

    private static void display(boolean[][] board) {
        for(boolean[] row: board){
            for(boolean element:row){
                if(element){
                    System.out.print("K ");
                }
                else{
                    System.out.print(". ");
                }
            }
            System.out.println();
        }
    }
}