bbb bbi bbk bbo bbs bbt bi- bib bii bik bio bis bit bkb bkk bko bks bkt bob boi bok boo bos bot bsb bsi bsk bso bss bst btb bti btk bto bts btt ibb ibi ibk ibo ibs ibt iib iii iio iis iit ikb iki ikk iko iks ikt io- iob ioi ioo ios iot is- isb isi isk iso iss ist itb iti itk ito its itt k-t kbb kbi kbk kbo kbs kib kii kik kio kis kit kkb kki kkk kks kkt kob koi kok koo kos kot ksb ksi ksk kso kss kst ktb ktk kto kts ktt o-i ob- obb obi obk obo obs obt oib oii oik oio ois oit okb oki okk oko oks oo- oob ooi ook ooo oos oot os- osb osi osk oso oss ost ot- otb oti otk oto ots ott sbb sbi sbk sbo sbs sbt sib sii sik sio sis sit sk- skb ski skk sko sks skt sob soi sok soo sos sot ss- ssb ssi ssk sso sss sst stb sti stk sto sts stt tbb tbi tbk tbo tbs tbt tib tii tik tio tis tit tkb tkk tko tks tkt to- tob toi tok too tos tot tsb tsi tsk tso tss tst ttb tti ttk tto tts ttt