-ic a-a a-b a-c a-i a-t aaa aab aac aai aao aat ab- aba abb abc abi abo abt ac- aca acb acc aci aco act ai- aia aib aic aii aio ait aoa aob aoc aoi aoo aot at- ata atb atc ati ato att baa bab bac bai bao bat bba bbb bbc bbi bbo bbt bca bcb bcc bci bco bct bi- bia bib bic bii bio bit boa bob boc boi boo bot bta btb btc bti bto btt c-- caa cab cac cai cao cat cba cbb cbc cbi cbo cbt cca ccb ccc cci cco cct ci- cia cib cic cii cio cit co- coa cob coc coi coo cot cta ctb ctc cti cto ctt ia- iaa iab iac iai iao iat iba ibb ibc ibi ibo ibt ica icb icc ici ico ict iia iib iic iii iio iit io- ioa iob ioc ioi ioo iot ita itb itc iti ito itt o-i oaa oab oac oai oao oat ob- oba obb obc obi obo obt oc- oca ocb occ oci oco oct oia oib oic oii oio oit oo- ooa oob ooc ooi ooo oot ot- ota otb otc oti oto ott taa tab tac tai tao tat tba tbb tbc tbi tbo tbt tca tcb tcc tci tco tct tia tib tic tii tio tit to- toa tob toc toi too tot tta ttb ttc tti tto ttt