-ic bbb bbc bbi bbk bbo bcb bcc bci bck bco bi- bib bic bii bik bio bkb bkc bkk bko bob boc boi bok boo c-- cbb cbc cbi cbk cbo ccb ccc cci cck cco ci- cib cic cii cik cio ckb ckc cki cko co- cob coc coi cok coo ibb ibc ibi ibk ibo icb icc ici ick ico iib iic iii iio ikb ikc iki ikk iko io- iob ioc ioi ioo kbb kbc kbi kbk kbo kcb kcc kci kck kib kic kii kik kio kkb kkc kki kkk kob koc koi kok koo o-i ob- obb obc obi obk obo oc- ocb occ oci ock oco oib oic oii oik oio okb okc oki okk oko oo- oob ooc ooi ook ooo