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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very hard (0)

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

Difficulty: Very easy (0)