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

Difficulty: Very hard (0)

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

Difficulty: Easy (0)

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

Difficulty: Easy (0)

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

Difficulty: Very easy (0)