-er a-a a-c a-t aaa aac aae aak aao aar aas aat ac- aca acc ace ack aco acr acs act aea aec aee aek aeo aer aes aet aka akc ake akk ako akr aks aoa aoc aoe aok aoo aor aos aot ar- ara arc are ark aro arr ars art as- asa asc ase ask aso asr ass ast at- ata atc ate ato atr ats att c-- caa cac cae cak cao car cas cat cca ccc cce cck cco ccr ccs cct ce- cea cec cee cek ceo cer ces cet cka ckc cko cks ckt co- coa coc coe cok coo cor cos cot cra crc cre crk cro crr crs crt csa csc cse csk cso csr css cst cta ctc cte ctk cto ctr cts ctt eaa eac eae eak eao ear eas eat ec- eca ecc ece eck eco ecr ecs ect eea eec eee eek eeo eer ees eet eka ekc eke eko ekr eks ekt eo- eoa eoc eoe eok eoo eor eos eot era erc ere erk ero err ers ert es- esa esc ese esk eso esr ess est eta etc ete etk eto etr ets ett k-t ka- kaa kac kae kak kao kar kas kat kca kcc kce kck kcr kcs kct ke- kea kec kee kek keo ker kes ket kkc kke kkk kkr kks kkt koa koc koe kok koo kor kos kot kra krc krk kro krr krs krt ksa ksc kse ksk kso ksr kss kst kta ktc kte ktk kto ktr kts ktt oaa oac oae oak oao oar oas oat oc- oca occ ock oco ocr ocs oct oea oec oee oeo oer oes oet oka okc oke okk oko okr oks oo- ooa ooc ook ooo oor oos oot or- ora orc ore ork oro orr ors ort os- osa osc ose osk oso osr oss ost ot- ota otc ote otk oto otr ots ott ra- raa rac rae rak rao rar ras rat rca rcc rce rco rcr rcs rct re- rea rec ree rek reo rer res ret rkc rke rkk rko rks rkt roa roc roe rok roo ror ros rot rra rrc rrk rrr rrs rrt rsa rsc rse rsk rso rsr rss rst rta rtc rte rtk rto rtr rts rtt saa sac sae sak sao sar sas sat sca scc sce sck sco scr scs sct se- sea sec see sek seo ser ses set sk- ska skc ske skk sko skr sks skt soa soc soe sok soo sor sos sot sr- sra src sre srk sro srr srs srt ss- ssa ssc sse ssk sso ssr sss sst sta stc ste stk sto str sts stt taa tac tae tak tao tar tas tat tca tcc tce tck tco tcr tcs tct te- tea tec tee tek teo ter tes tet tka tkc tke tkk tko tkr tks tkt to- toa toc toe tok too tor tos tot tra trc tre trk tro trr trs trt tsa tsc tse tsk tso tsr tss tst tta ttc tte ttk tto ttr tts ttt