(set-info :smt-lib-version 2.6)
(set-logic QF_S)
(set-option :strings-exp true)
(set-info :status sat)
(declare-fun s () String)
;(assert (= s "")))
(assert (str.contains joined ""))
; ()+
(assert (str.in_re joined
(re.+ (re.++
(str.to_re "")
))
))
(check-sat)