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

Difficulty: Very hard (0)

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

Difficulty: Very hard (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)