(VAR )
(RULES
  f(b) -> a
  f(b) -> f(c)
  f(c) -> f(b)
  f(c) -> d
  b -> e
  c -> e'
  f(e) -> a
  f(e') -> d
)
(COMMENT
[11] Example 3.3.2
submitted by: Takahito Aoto, Junichi Yoshida, and Yoshihito Toyama
)