(SIG
   (f   o -> o)
   (c   -> o)
   (a   -> o)
   (h   o o -> o)
   (b   -> o)
)
(RULES
   f(c) -> a
   f(a) -> c
   c -> f(h(a,h(f(c),c)))
   h(f(c),f(b)) -> f(h(a,c))
)