-er a-a a-c a-t aaa aac aad aae aak aao aar aat ac- aca acc acd ace ack aco acr act ad- ada adc add ade adk ado adr adt aea aec aed aee aek aeo aer aet aka akc akd ake akk ako akr aoa aoc aod aoe aok aoo aor aot ar- ara arc ard are ark aro arr art at- ata atc atd ate ato atr att c-- caa cac cad cae cak cao car cat cca ccc ccd cce cck cco ccr cct cda cdc cdd cde cdk cdo cdr cdt ce- cea cec ced cee cek ceo cer cet cka ckc ckd cko ckt co- coa coc cod coe cok coo cor cot cra crc crd cre crk cro crr crt cta ctc ctd cte ctk cto ctr ctt daa dac dad dae dak dao dar dat dca dcc dcd dce dck dco dcr dct dda ddc ddd dde ddk ddo ddr ddt de- dea dec ded dee dek deo der det dka dkc dke dkk dko dkr dkt doa doc dod doe dok doo dor dot dra drc drd dre drk dro drr drt dta dtc dtd dte dtk dto dtr dtt eaa eac ead eae eak eao ear eat ec- eca ecc ecd ece eck eco ecr ect ed- eda edc edd ede edk edo edr edt eea eec eed eee eek eeo eer eet eka ekc ekd eke eko ekr ekt eo- eoa eoc eod eoe eok eoo eor eot era erc erd ere erk ero err ert eta etc etd ete etk eto etr ett k-t ka- kaa kac kad kae kak kao kar kat kca kcc kcd kce kck kcr kct kda kdc kde kdk kdo kdr kdt ke- kea kec ked kee kek keo ker ket kkc kke kkk kkr kkt koa koc kod koe kok koo kor kot kra krc krd krk kro krr krt kta ktc kte ktk kto ktr ktt oaa oac oad oae oak oao oar oat oc- oca occ ocd ock oco ocr oct oda odc odd ode odo odr odt oea oec oed oee oeo oer oet oka okc okd oke okk oko okr oo- ooa ooc ood ook ooo oor oot or- ora orc ord ore ork oro orr ort ot- ota otc otd ote otk oto otr ott ra- raa rac rad rae rak rao rar rat rca rcc rcd rce rco rcr rct rda rdc rdd rde rdo rdr rdt re- rea rec red ree rek reo rer ret rkc rke rkk rko rkt roa roc rod roe rok roo ror rot rra rrc rrd rrk rrr rrt rta rtc rtd rte rtk rto rtr rtt taa tac tad tae tak tao tar tat tca tcc tcd tce tck tco tcr tct tda tdc tdd tde tdk tdo tdr tdt te- tea tec ted tee tek teo ter tet tka tkc tke tkk tko tkr tkt to- toa toc tod toe tok too tor tot tra trc trd tre trk tro trr trt tta ttc ttd tte ttk tto ttr ttt