4		9					7
					4
5	6		9		1	4
	2	7	6	5	9		1
3			4	1	5			2
	7		1	2	8	5	4
		4	5		3		9	7
			7
	5					1		3

Difficulty: Very easy (0)

1		2		6			8
	8						5	9
		1	8			3		6
	6	4	3	9		7		8
			9		7
8		7		1	5	6	9
2		8			6	1
9	4						6
	7			3		4		1

Difficulty: Very easy (0)

8		6				9
2			7	8	1			5
	8	5	3			6	2
	1			7			3	2
			4	9	6
3	4			2			5
	2	1			5	7	9
6			1	5	3			8
		3				5		9

Difficulty: Very easy (0)

	2				3
	8	4	3	6		2
			5	3	4			7
4					9	8
2		8		1		4		3
		6	1					5
3			2	5	6
		5		8	2	6	1
			7				8

Difficulty: Very hard (0)