bbb bbi bbk bbo bbr bbs bbt bi- bib bii bik bio bir bis bit bkb bkk bko bkr bks bkt bob boi bok boo bor bos bot brb bri brk bro brr brs brt bsb bsi bsk bso bsr bss bst btb bti btk bto btr bts btt ibb ibi ibk ibo ibr ibs ibt iib iii iio iir iis iit ikb iki ikk iko ikr iks ikt io- iob ioi ioo ior ios iot ir- irb iri irk iro irr irs irt is- isb isi isk iso isr iss ist itb iti itk ito its itt k-t kbb kbi kbk kbo kbr kbs kib kii kik kio kir kis kit kkb kki kkk kkr kks kkt kob koi kok koo kor kos kot kri krk kro krr krs krt ksb ksi ksk kso ksr kss kst ktb ktk kto ktr kts ktt o-i ob- obb obi obk obo obr obs obt oib oii oik oio oir ois oit okb oki okk oko okr oks oo- oob ooi ook ooo oor oos oot or- orb ori ork oro orr ors ort os- osb osi osk oso osr oss ost ot- otb oti otk oto otr ots ott rbb rbi rbk rbo rbr rbs rbt rib rii rik rio rir ris rit rkb rkk rko rks rkt rob roi rok roo ror ros rot rrb rri rrk rrr rrs rrt rsb rsi rsk rso rsr rss rst rtb rti rtk rto rtr rts rtt sbb sbi sbk sbo sbr sbs sbt sib sii sik sio sir sis sit sk- skb ski skk sko skr sks skt sob soi sok soo sor sos sot sr- srb sri srk sro srr srs srt ss- ssb ssi ssk sso ssr sss sst stb sti stk sto str sts stt tbb tbi tbk tbo tbr tbs tbt tib tii tik tio tir tis tit tkb tkk tko tkr tks tkt to- tob toi tok too tor tos tot trb tri trk tro trr trs trt tsb tsi tsk tso tsr tss tst ttb tti ttk tto ttr tts ttt