a-a a-c a-t aaa aac aao aar aat ac- aca acc aco acr act aoa aoc aoo aor aot ar- ara arc aro arr art at- ata atc ato atr att c-- caa cac cao car cat cca ccc cco ccr cct co- coa coc coo cor cot cra crc cro crr crt cta ctc cto ctr ctt oaa oac oao oar oat oc- oca occ oco ocr oct oo- ooa ooc ooo oor oot or- ora orc oro orr ort ot- ota otc oto otr ott ra- raa rac rao rar rat rca rcc rco rcr rct roa roc roo ror rot rra rrc rrr rrt rta rtc rto rtr rtt taa tac tao tar tat tca tcc tco tcr tct to- toa toc too tor tot tra trc tro trr trt tta ttc tto ttr ttt