end of (B)
(c) ( (A) ) ----> (C)
(a)
e ( (C) )
(b) ( (B) )
4 ( (c) )
(c) ( (X) )
(C) ( (Y) )
4 ( (1):(3) )
2 or b
3 ( 3)
c ( W ) ( 2 or B )
Y
(v) ( (5) )
3 ( 5 )
(c) Y
5 ( C )
B ( (Z) ) or 2 ( A ( (Z) ) )