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

Difficulty: Easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Hard (0)