hard 9×9 Set 1 Grid Puzzle
9
6
1
5
2
4
6
1
7
5
9
4
2
1
1
6
4
3
7
2
6
1
8
3
2
7
1
8
4
8
9
3
1
5
9
7
2
1
3
5
8
7
2
1