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