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

Difficulty: Very easy (0)

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

Difficulty: Easy (0)

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

Difficulty: Very hard (0)

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

Difficulty: Very easy (0)