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