-er a-a a-c a-t aaa aac aae aak aao aar aat ac- aca acc ace ack aco acr act aea aec aee aek aeo aer aet aka akc ake akk ako akr aoa aoc aoe aok aoo aor aot ar- ara arc are ark aro arr art at- ata atc ate ato atr att c-- caa cac cae cak cao car cat cca ccc cce cck cco ccr cct ce- cea cec cee cek ceo cer cet cka ckc cko ckt co- coa coc coe cok coo cor cot cra crc cre crk cro crr crt cta ctc cte ctk cto ctr ctt eaa eac eae eak eao ear eat ec- eca ecc ece eck eco ecr ect eea eec eee eek eeo eer eet eka ekc eke eko ekr ekt eo- eoa eoc eoe eok eoo eor eot era erc ere erk ero err ert eta etc ete etk eto etr ett k-t ka- kaa kac kae kak kao kar kat kca kcc kce kck kcr kct ke- kea kec kee kek keo ker ket kkc kke kkk kkr kkt koa koc koe kok koo kor kot kra krc krk kro krr krt kta ktc kte ktk kto ktr ktt oaa oac oae oak oao oar oat oc- oca occ ock oco ocr oct oea oec oee oeo oer oet oka okc oke okk oko okr oo- ooa ooc ook ooo oor oot or- ora orc ore ork oro orr ort ot- ota otc ote otk oto otr ott ra- raa rac rae rak rao rar rat rca rcc rce rco rcr rct re- rea rec ree rek reo rer ret rkc rke rkk rko rkt roa roc roe rok roo ror rot rra rrc rrk rrr rrt rta rtc rte rtk rto rtr rtt taa tac tae tak tao tar tat tca tcc tce tck tco tcr tct te- tea tec tee tek teo ter tet tka tkc tke tkk tko tkr tkt to- toa toc toe tok too tor tot tra trc tre trk tro trr trt tta ttc tte ttk tto ttr ttt