a-a a-c a-t aaa aac aao aar aas aat ac- aca acc aco acr acs act aoa aoc aoo aor aos aot ar- ara arc aro arr ars art as- asa asc aso asr ass ast at- ata atc ato atr ats att c-- caa cac cao car cas cat cca ccc cco ccr ccs cct co- coa coc coo cor cos cot cra crc cro crr crs crt csa csc cso csr css cst cta ctc cto ctr cts ctt oaa oac oao oar oas oat oc- oca occ oco ocr ocs oct oo- ooa ooc ooo oor oos oot or- ora orc oro orr ors ort os- osa osc oso osr oss ost ot- ota otc oto otr ots ott ra- raa rac rao rar ras rat rca rcc rco rcr rcs rct roa roc roo ror ros rot rra rrc rrr rrs rrt rsa rsc rso rsr rss rst rta rtc rto rtr rts rtt saa sac sao sar sas sat sca scc sco scr scs sct soa soc soo sor sos sot sr- sra src sro srr srs srt ss- ssa ssc sso ssr sss sst sta stc sto str sts stt taa tac tao tar tas tat tca tcc tco tcr tcs tct to- toa toc too tor tos tot tra trc tro trr trs trt tsa tsc tso tsr tss tst tta ttc tto ttr tts ttt