-er a-a a-c a-t aaa aac aae aak aan aao aar aat ac- aca acc ace ack acn aco acr act aea aec aee aek aen aeo aer aet aka akc ake akk akn ako akr an- ana anc ane ank ann ano anr ant aoa aoc aoe aok aon aoo aor aot ar- ara arc are ark arn aro arr art at- ata atc ate atn ato atr att c-- caa cac cae cak can cao car cat cca ccc cce cck ccn cco ccr cct ce- cea cec cee cek cen ceo cer cet cka ckc cko ckt cn- cna cnc cne cnn cno cnr cnt co- coa coc coe cok con coo cor cot cra crc cre crk crn cro crr crt cta ctc cte ctk ctn cto ctr ctt eaa eac eae eak ean eao ear eat ec- eca ecc ece eck ecn eco ecr ect eea eec eee eek een eeo eer eet eka ekc eke eko ekr ekt en- ena enc ene enk enn eno enr ent eo- eoa eoc eoe eok eon eoo eor eot era erc ere erk ern ero err ert eta etc ete etk etn eto etr ett k-t ka- kaa kac kae kak kan kao kar kat kca kcc kce kck kcn kcr kct ke- kea kec kee kek ken keo ker ket kkc kke kkk kkn kkr kkt kn- kna knc kne knk knn kno knr knt koa koc koe kok kon koo kor kot kra krc krk krn kro krr krt kta ktc kte ktk ktn kto ktr ktt naa nac nae nak nan nao nar nat nca ncc nce nck ncn nco ncr nct ne- nea nec nee nek nen neo ner net nka nkc nke nkk nkn nko nkr nkt nna nnc nne nnk nnn nno nnt no- noa noc noe nok non noo nor not nra nrc nre nrk nrn nro nrr nrt nta ntc nte ntk ntn nto ntr ntt oaa oac oae oak oan oao oar oat oc- oca occ ock ocn oco ocr oct oea oec oee oen oeo oer oet oka okc oke okk oko okr on- ona onc one onk onn ono onr ont oo- ooa ooc ook oon ooo oor oot or- ora orc ore ork orn oro orr ort ot- ota otc ote otk otn oto otr ott ra- raa rac rae rak ran rao rar rat rca rcc rce rcn rco rcr rct re- rea rec ree rek ren reo rer ret rkc rke rkk rko rkt rna rnc rnn rno rnr rnt roa roc roe rok ron roo ror rot rra rrc rrk rrn rrr rrt rta rtc rte rtk rtn rto rtr rtt taa tac tae tak tan tao tar tat tca tcc tce tck tcn tco tcr tct te- tea tec tee tek ten teo ter tet tka tkc tke tkk tko tkr tkt tna tnc tne tnk tnn tno tnr tnt to- toa toc toe tok ton too tor tot tra trc tre trk trn tro trr trt tta ttc tte ttk ttn tto ttr ttt