a-a a-c a-t aaa aac aao aar aas aat aax ac- aca acc aco acr acs act acx aoa aoc aoo aor aos aot aox ar- ara arc aro arr ars art arx as- asa asc aso asr ass ast asx at- ata atc ato atr ats att atx ax- axa axo axr axs axt axx c-- caa cac cao car cas cat cax cca ccc cco ccr ccs cct ccx co- coa coc coo cor cos cot cox cra crc cro crr crs crt crx csa csc cso csr css cst csx cta ctc cto ctr cts ctt ctx cxc cxo cxr cxs cxt cxx oaa oac oao oar oas oat oax oc- oca occ oco ocr ocs oct ocx oo- ooa ooc ooo oor oos oot oox or- ora orc oro orr ors ort orx os- osa osc oso osr oss ost osx ot- ota otc oto otr ots ott ox- oxa oxc oxo oxt oxx ra- raa rac rao rar ras rat rax rca rcc rco rcr rcs rct rcx roa roc roo ror ros rot rox rra rrc rrr rrs rrt rsa rsc rso rsr rss rst rsx rta rtc rto rtr rts rtt rtx rxr rxs saa sac sao sar sas sat sax sca scc sco scr scs sct scx soa soc soo sor sos sot sox sr- sra src sro srr srs srt srx ss- ssa ssc sso ssr sss sst ssx sta stc sto str sts stt stx sxc sxs sxt t-x taa tac tao tar tas tat tax tca tcc tco tcr tcs tct tcx to- toa toc too tor tos tot tox tra trc tro trr trs trt trx tsa tsc tso tsr tss tst tsx tta ttc tto ttr tts ttt ttx txs txt xaa xac xar xas xat xcr xcx xoa xoc xoo xor xos xot xox xrc xrt xrx xsa xsc xss xst xtc xtr xts xtx xxo xxx