4			1	3
5
					2
	5	3			6

Difficulty: Super easy (0)

					4
4			2
3
					5
		6			3
5

Difficulty: Easy (0)

			3
		3	6		4
1		4	5
		2

Difficulty: Very easy (0)

4	2				5
	1
				6
1				4	6

Difficulty: Very hard (0)