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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Medium (0)

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

Difficulty: Very easy (0)