-ic a-a a-b a-c a-i aaa aab aac aai aao ab- aba abb abc abi abo ac- aca acb acc aci aco ai- aia aib aic aii aio aoa aob aoc aoi aoo baa bab bac bai bao bba bbb bbc bbi bbo bca bcb bcc bci bco bi- bia bib bic bii bio boa bob boc boi boo c-- caa cab cac cai cao cba cbb cbc cbi cbo cca ccb ccc cci cco ci- cia cib cic cii cio co- coa cob coc coi coo ia- iaa iab iac iai iao iba ibb ibc ibi ibo ica icb icc ici ico iia iib iic iii iio io- ioa iob ioc ioi ioo o-i oaa oab oac oai oao ob- oba obb obc obi obo oc- oca ocb occ oci oco oia oib oic oii oio oo- ooa oob ooc ooi ooo