4	5
			7		9
				1
				6
			4		5
						1	8

Difficulty: Easy (0)

			5
		9					3	2
		1	2
		4				1
					9	4
4	5					3
					8

Difficulty: Very easy (0)

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

Difficulty: Very hard (0)

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

Difficulty: Easy (0)