a-a a-c a-t aaa aac aao aas aat ac- aca acc aco acs act aoa aoc aoo aos aot as- asa asc aso ass ast at- ata atc ato ats att c-- caa cac cao cas cat cca ccc cco ccs cct co- coa coc coo cos cot csa csc cso css cst cta ctc cto cts ctt oaa oac oao oas oat oc- oca occ oco ocs oct oo- ooa ooc ooo oos oot os- osa osc oso oss ost ot- ota otc oto ots ott saa sac sao sas sat sca scc sco scs sct soa soc soo sos sot ss- ssa ssc sso sss sst sta stc sto sts stt taa tac tao tas tat tca tcc tco tcs tct to- toa toc too tos tot tsa tsc tso tss tst tta ttc tto tts ttt