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

Difficulty: Easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Medium (0)