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

Difficulty: Very hard (0)

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

Difficulty: Very easy (0)

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

Difficulty: Easy (0)

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

Difficulty: Very hard (0)