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

Difficulty: Super easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very hard (0)

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

Difficulty: Super easy (0)