n1 p2
r2
t1
s2
n2
n3
r1
n1 p3
n1 r2
n1 s1
n1 p1
n1
n1 n2 p1
n1 r2 s3
n2 n1
t2
n1 r3
p2
n1 n2 p3
n1 n2 t2
n1 n2 t3
n1 p2 p3
p1 p3
n1 t3 s3
n1 n2 n3
n2 t3
n1 n2 s4
r2 r3 t2
n2 t2
n1 n2 r2
n1 s4 r2 t2
p3 r3
p1
n1 s2
n1 s4
n1 p4 t3
n1 p1 s2
n1 t1 t3
n1 p2 t3
n3 r2 s1
n3 p1