(CONDITIONTYPE ORIENTED)
(VAR x y)
(RULES
 f(x,y) -> g(s(x)) | c(g(x)) == c(a)
 f(x,y) -> h(s(x)) | c(h(x)) == c(a)
 g(s(x)) -> x
 h(s(x)) -> x
 b -> b
)