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)

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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Easy (0)