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

Difficulty: Very hard (0)

8		4		6	3
	6			4			8
		1
4		6	3
				8	4		1
					6
5			2			4
		8	6		2		5

Difficulty: Very easy (0)

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

Difficulty: Easy (0)

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

Difficulty: Easy (0)