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