-er a-a a-c a-t aaa aac aae aao aap aar aat ac- aca acc ace aco acp acr act aea aec aee aeo aep aer aet aoa aoc aoe aoo aop aor aot ap- apa apc ape apo app apr apt ar- ara arc are aro arp arr art at- ata atc ate ato atp atr att c-- caa cac cae cao cap car cat cca ccc cce cco ccp ccr cct ce- cea cec cee ceo cep cer cet co- coa coc coe coo cop cor cot cpa cpc cpe cpo cpp cpr cpt cra crc cre cro crp crr crt cta ctc cte cto ctp ctr ctt eaa eac eae eao eap ear eat ec- eca ecc ece eco ecr ect eea eec eee eeo eep eer eet eo- eoa eoc eoe eoo eop eor eot ep- epa epc epe epo epp epr ept era erc ere ero erp err ert eta etc ete eto etp etr ett oaa oac oae oao oap oar oat oc- oca occ oco ocp ocr oct oea oec oee oeo oep oer oet oo- ooa ooc ooo oop oor oot op- opa opc ope opo opp opr opt or- ora orc ore oro orp orr ort ot- ota otc ote oto otp otr ott p-p paa pac pae pao pap par pat pca pcc pce pco pcp pcr pct pea pec pee peo pep per pet poa poc poe poo pop por pot ppa ppc ppe ppo ppp ppr ppt pra prc pre pro prp prr prt pt- pta ptc pte pto ptp ptr ptt ra- raa rac rae rao rap rar rat rca rcc rce rco rcp rcr rct re- rea rec ree reo rep rer ret roa roc roe roo rop ror rot rpa rpc rpe rpo rpp rpr rpt rra rrc rrp rrr rrt rta rtc rte rto rtp rtr rtt taa tac tae tao tap tar tat tca tcc tce tco tcp tcr tct te- tea tec tee teo tep ter tet to- toa toc toe too top tor tot tpa tpc tpe tpo tpp tpr tpt tra trc tre tro trp trr trt tta ttc tte tto ttp ttr ttt