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

Difficulty: Hard (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Super easy (0)