a-a a-c a-t aaa aac aaf aao aas aat ac- aca acc acf aco acs act af- afa afc aff afo afs aft aoa aoc aof aoo aos aot as- asa asc asf aso ass ast at- ata atc atf ato ats att c-- caa cac caf cao cas cat cca ccc ccf cco ccs cct cfa cfc cff cfo cfs cft co- coa coc cof coo cos cot csa csc csf cso css cst cta ctc ctf cto cts ctt faa fac faf fao fas fat fca fcc fcf fco fcs fct ffa ffc fff ffo ffs fft foa foc fof foo fos fot fsa fsc fsf fso fss fst fta ftc ftf fto fts ftt oaa oac oaf oao oas oat oc- oca occ ocf oco ocs oct of- ofa ofc off ofo ofs oft oo- ooa ooc oof ooo oos oot os- osa osc osf oso oss ost ot- ota otc otf oto ots ott saa sac saf sao sas sat sca scc scf sco scs sct sfa sfc sff sfo sfs sft soa soc sof soo sos sot ss- ssa ssc ssf sso sss sst sta stc stf sto sts stt taa tac taf tao tas tat tca tcc tcf tco tcs tct tfa tfc tff tfo tfs tft to- toa toc tof too tos tot tsa tsc tsf tso tss tst tta ttc ttf tto tts ttt