b-u bbb bbi bbk bbr bbs bbu bi- bib bii bik bir bis biu bkb bkk bkr bks brb bri brk brr brs bru bsb bsi bsk bsr bss bsu bub bui buk bur bus buu ibb ibi ibk ibr ibs ibu iib iii iir iis iiu ikb iki ikk ikr iks iku ir- irb iri irk irr irs iru is- isb isi isk isr iss isu iu- iub iui iur ius kbb kbi kbk kbr kbs kbu kib kii kik kir kis kiu kkb kki kkk kkr kks kku kri krk krr krs kru ksb ksi ksk ksr kss ksu kub kui kuk kur kus kuu rbb rbi rbk rbr rbs rbu rib rii rik rir ris rkb rkk rks rku rrb rri rrk rrr rrs rru rsb rsi rsk rsr rss rsu rub rui ruk rur rus ruu sbb sbi sbk sbr sbs sbu sib sii sik sir sis siu sk- skb ski skk skr sks sku sr- srb sri srk srr srs ss- ssb ssi ssk ssr sss ssu sub sui suk sur sus suu ubb ubi ubk ubr ubs ubu uib uii uir uis uiu ukb uki ukk ukr uku ur- urb uri urk urr urs uru usb usi usk usr uss usu uur uus uuu