b-u bbb bbi bbn bbr bbs bbt bbu bi- bib bii bin bir bis bit biu bnb bni bnn bnr bns bnt bnu brb bri brn brr brs brt bru bsb bsi bsn bsr bss bst bsu btb bti btn btr bts btt btu bub bui bun bur bus but buu ibb ibi ibn ibr ibs ibt ibu iib iii iin iir iis iit iiu in- inb ini inn inr ins int inu ir- irb iri irn irr irs irt iru is- isb isi isn isr iss ist isu itb iti itn its itt itu iu- iub iui iur ius iut n-i nbb nbi nbn nbr nbs nbt nbu nib nii nin nir nis nit niu nnb nni nnn nns nnt nnu nrb nri nrn nrr nrs nrt nru nsb nsi nsn nsr nss nst nsu ntb nti ntn ntr nts ntt ntu nub nui nun nur nus nut nuu rbb rbi rbn rbr rbs rbt rbu rib rii rin rir ris rit rnb rni rnn rnr rns rnt rnu rrb rri rrn rrr rrs rrt rru rsb rsi rsn rsr rss rst rsu rtb rti rtn rtr rts rtt rtu rub rui run rur rus rut ruu sbb sbi sbn sbr sbs sbt sbu sib sii sin sir sis sit siu snb sni snn snr sns snt snu sr- srb sri srn srr srs srt ss- ssb ssi ssn ssr sss sst ssu stb sti stn str sts stt stu sub sui sun sur sus sut suu tbb tbi tbn tbr tbs tbt tbu tib tii tin tir tis tit tiu tnb tni tnn tnr tns tnt trb tri trn trr trs trt tru tsb tsi tsn tsr tss tst tsu ttb tti ttn ttr tts ttt ttu tub tui tun tur tus tut tuu ubb ubi ubn ubr ubs ubt ubu uib uii uin uir uis uit uiu un- unb uni unn unr uns unt unu ur- urb uri urn urr urs urt uru usb usi usn usr uss ust usu utb uti utn utr uts utt utu uun uur uus uut uuu