(set-logic QF_UFLIAFS)
(set-info :status sat)
(declare-sort E 0)
(declare-fun s () (Set E))
(declare-fun t () (Set E))
(declare-fun u () (Set E))
(assert (>= (card s) 5))
(assert (>= (card t) 5))
(assert (<= (card u) 6))
(assert (= u (union s t)))
(check-sat)