b-u bbb bbi bbr bbs bbu bby bi- bib bii bir bis biu biy brb bri brr brs bru bry bsb bsi bsr bss bsu bsy bub bui bur bus buu buy by- byi byr bys byu ibb ibi ibr ibs ibu iby iib iii iir iis iiu ir- irb iri irr irs iru iry is- isb isi isr iss isu isy iu- iub iui iur ius iyr iys iyy rbb rbi rbr rbs rbu rib rii rir ris riy rrb rri rrr rrs rru rsb rsi rsr rss rsu rub rui rur rus ruu ruy ry- ryr rys ryu ryy sbb sbi sbr sbs sbu sby sib sii sir sis siu sr- srb sri srr srs sry ss- ssb ssi ssr sss ssu sub sui sur sus suu suy sy- syb syi syr sys syu ubb ubi ubr ubs ubu uby uib uii uir uis uiu ur- urb uri urr urs uru ury usb usi usr uss usu uur uus uuu uyi uys uyu ybi ybr ybs yby yii yir yis yrs yru ysb ysi ysr yss ysu ysy yui yur yus yuu yuy yyb yys yyu yyy