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

Difficulty: Medium

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

Difficulty: Medium

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

Difficulty: Easy

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

Difficulty: Medium