5							14
2			3	4		12	15				7			8
			1									10
					9				4		12				7
	7				12				15					14	16
1	4			15			11	2				5
	2			3	1
					2		4		16	12	9		11		1
4		16		1	3	2		9		6
										14	16			15
			7				9	4			5			2	11
9	15					6				2				5
7				14		8				13
			5									11
	10			2				14	5		8	3			12
3							1

Difficulty: Very easy (0)

12						13	2		1	6		5
			14				8	7
			1			5				8
							12							9
6				16					4			1
									7			3
	1	15	2	4		9			8
7			10					12				14	15
		2	11				13					15			9
						15			11		4	12	6	5
			9			11
			13			16					14				3
	8							6
					12				13			16
							11	9				6
			16		3	7		15	14						8

Difficulty: Hard (0)

6						14				16	4		10
									7						11
				3
				10	13	2				8		7			5
15						8	7				10	5
	16			11											15
					16						5	11		3
	9	3	8		14			1					2
		15					10			7		9	14	6
	14		1	16						5
12											13			11
			13	12				4	9						1
7			3		5				11	2	12
											6
14						13
		6		8	4				10						2

Difficulty: Easy (0)

						7		5					6
							6					12			16
14												4			13
		13	16			14			4	15		5			3
	13		12			11									4
					8
							10		3		13
		7						4	8	6					15
15					4	8	14						16
				9		1		16
										7
11									9			10		6
13			11		7	12			2			16	9
10			1												11
6			5					7
		16					4		6

Difficulty: Easy (0)