b-u bbb bbi bbr bbs bbt bbu bby bi- bib bii bir bis bit biu biy brb bri brr brs brt bru bry bsb bsi bsr bss bst bsu bsy btb bti btr bts btt btu bty bub bui bur bus but buu buy by- byi byr bys byt byu ibb ibi ibr ibs ibt ibu iby iib iii iir iis iit iiu ir- irb iri irr irs irt iru iry is- isb isi isr iss ist isu isy itb iti its itt itu ity iu- iub iui iur ius iut iyr iys iyt iyy rbb rbi rbr rbs rbt rbu rib rii rir ris rit riy rrb rri rrr rrs rrt rru rsb rsi rsr rss rst rsu rtb rti rtr rts rtt rtu rty rub rui rur rus rut ruu ruy ry- ryr rys ryu ryy sbb sbi sbr sbs sbt sbu sby sib sii sir sis sit siu sr- srb sri srr srs srt sry ss- ssb ssi ssr sss sst ssu stb sti str sts stt stu sty sub sui sur sus sut suu suy sy- syb syi syr sys syt syu tbb tbi tbr tbs tbt tbu tib tii tir tis tit tiu tiy trb tri trr trs trt tru try tsb tsi tsr tss tst tsu tsy ttb tti ttr tts ttt ttu tty tub tui tur tus tut tuu tuy tyr tys tyt ubb ubi ubr ubs ubt ubu uby uib uii uir uis uit uiu ur- urb uri urr urs urt uru ury usb usi usr uss ust usu utb uti utr uts utt utu uty uur uus uut uuu uyi uys uyu ybi ybr ybs yby yii yir yis yit yrs yrt yru ysb ysi ysr yss yst ysu ysy ytr yts ytt ytu yui yur yus yut yuu yuy yyb yys yyt yyu yyy