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

Difficulty: Very easy (0)

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

Difficulty: Easy (0)

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

Difficulty: Super easy (0)

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

Difficulty: Very easy (0)