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

Difficulty: Very hard (0)

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

Difficulty: Super easy (0)

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

Difficulty: Medium (0)

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

Difficulty: Very easy (0)