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