Hard Level 9 (28 clues)

谜题网址: http://cn.sudoku99.com/sudoku9x9/puzzle/244431/
网站: cn.sudoku99.com

1

6

8

2

7

6

4

2

3

5

3

9

1

7

4

1

2

5

1

9

5

6

8

7

1

1

4

7