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

Difficulty: Very hard (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very hard (0)

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

Difficulty: Very easy (0)