(set-logic QF_BV)
(declare-fun x () (_ BitVec 2))
(declare-fun y () (_ BitVec 2))
(declare-fun fx () (_ BitVec 2))
(declare-fun fy () (_ BitVec 2))
(assert (and (= x fy) (= y fx) (distinct x y) (=> (= x y) (= fx fy))))
(check-sat)
(exit)