b-u bbb bbi bbr bbs bbt bbu bbx bi- bib bii bir bis bit biu bix brb bri brr brs brt bru brx bsb bsi bsr bss bst bsu bsx btb bti btr bts btt btu btx bub bui bur bus but buu bux bxb bxi bxx ibb ibi ibr ibs ibt ibu ibx iib iii iir iis iit iiu iix ir- irb iri irr irs irt iru irx is- isb isi isr iss ist isu itb iti its itt itu itx iu- iub iui iur ius iut ixi rbb rbi rbr rbs rbt rbu rbx rib rii rir ris rit rix rrb rri rrr rrs rrt rru rsb rsi rsr rss rst rsu rsx rtb rti rtr rts rtt rtu rtx rub rui rur rus rut ruu rux rxr rxs sbb sbi sbr sbs sbt sbu sbx sib sii sir sis sit siu six sr- srb sri srr srs srt srx ss- ssb ssi ssr sss sst ssu ssx stb sti str sts stt stu stx sub sui sur sus sut suu sux sxi sxs sxt sxu t-x tbb tbi tbr tbs tbt tbu tib tii tir tis tit tiu tix trb tri trr trs trt tru trx tsb tsi tsr tss tst tsu tsx ttb tti ttr tts ttt ttu ttx tub tui tur tus tut tuu tux txi txs txt txu ubb ubi ubr ubs ubt ubu ubx uib uii uir uis uit uiu ur- urb uri urr urs urt uru urx usb usi usr uss ust usu usx utb uti utr uts utt utu utx uur uus uut uuu uxb uxr uxt uxu xbr xbx xii xis xit xiu xix xrt xrx xsb xsi xss xst xti xtr xts xtx xui xus xxi xxx