Problem:
 c() -> h(c(),c())
 f(c()) -> c()
 f(b()) -> b()
 a() -> b()
 a() -> h(h(a(),a()),h(c(),b()))

Proof:
 Nonconfluence Processor:
  terms: b() *<- a() ->* h(h(a(),a()),h(c(),b()))
  Qed