mat		s1	s2	s3	s4	s5	s6	s7	s8
s1		1	0	1	0	0	0	0	0
s2		0	0	0	0	1	0	0	0
s3		0	1	0	1	0	0	0	0
s4		0	0	0	0	0	0	1	0
s5		1	0	1	0	0	0	0	0
s6		0	0	0	0	1	0	0	0
s7		0	1	0	1	0	0	0	0
s8		0	0	0	0	0	0	1	0