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

Proof:
 Uncurry Processor:
  f5(f(),f5(f(),f5(f(),b()))) -> b()
  f5(f5(h(),f5(f5(h(),a()),a())),f5(f5(h(),f5(f(),f5(f(),a()))),f5(f5(h(),c()),b()))) ->
  f5(f(),c())
  Ground Confluence Processor:
   confluent by decision procedure.