2 4
 1	1	0	0
 1	0	1	0

-1

20 8
 
 0	-1	0	0	0	0	0	2
 0	0	-1	0	0	0	0	1
 0	0	0	-1	0	0	0	2
 0	0	0	0	-1	0	0	4
 1	0	0	0	1	0	0	-2
 1	-2	0	2	1	0	0	-4
 1	0	0	0	-1	0	1	-1
 1	2	0	-2	-1	0	0	5
 1	0	0	1	0	0	0	-1
 1	0	-2	1	0	0	0	0
 1	-2	0	2	0	0	1	-5
 1	0	0	-1	0	1	0	0
 1	0	2	-1	0	0	0	1
 1	2	0	-2	0	0	0	3
 1	0	1	0	0	0	0	0
 1	-2	4	0	0	0	1	-3
 1	0	-2	0	0	1	0	0
 1	2	-4	0	0	0	0	3
 1	2	0	0	0	0	0	1
 1	-2	0	0	0	2	1	-5