3
		9					7
						1
		5				3
		4
	8					9
					6

Difficulty: Easy (0)

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

Difficulty: Easy (0)

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

Difficulty: Very hard (0)

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

Difficulty: Very hard (0)