-ic a-a a-b a-c a-i a-t aaa aab aac aaf aai aat ab- aba abb abc abf abi abt ac- aca acb acc acf aci act af- afa afb afc aff afi aft ai- aia aib aic aif aii ait at- ata atb atc atf ati att baa bab bac baf bai bat bba bbb bbc bbf bbi bbt bca bcb bcc bcf bci bct bfa bfb bfc bff bfi bft bi- bia bib bic bif bii bit bta btb btc btf bti btt c-- caa cab cac caf cai cat cba cbb cbc cbf cbi cbt cca ccb ccc ccf cci cct cfa cfb cfc cff cfi cft ci- cia cib cic cif cii cit cta ctb ctc ctf cti ctt faa fab fac faf fai fat fba fbb fbc fbf fbi fbt fca fcb fcc fcf fci fct ffa ffc fff ffi fft fia fib fic fif fii fit fta ftb ftc ftf fti ftt i-f ia- iaa iab iac iaf iai iat iba ibb ibc ibf ibi ibt ica icb icc icf ici ict ifa ifb ifc iff ifi ift iia iib iic iif iii iit ita itb itc itf iti itt taa tab tac taf tai tat tba tbb tbc tbf tbi tbt tca tcb tcc tcf tci tct tfa tfb tfc tff tfi tft tia tib tic tif tii tit tta ttb ttc ttf tti ttt