-er a-a a-c a-t aaa aac aae aap aar aas aat ac- aca acc ace acp acr acs act aea aec aee aep aer aes aet ap- apa apc ape app apr aps apt ar- ara arc are arp arr ars art as- asa asc ase asp asr ass ast at- ata atc ate atp atr ats att c-- caa cac cae cap car cas cat cca ccc cce ccp ccr ccs cct ce- cea cec cee cep cer ces cet cpa cpc cpe cpp cpr cps cpt cra crc cre crp crr crs crt csa csc cse csp csr css cst cta ctc cte ctp ctr cts ctt eaa eac eae eap ear eas eat ec- eca ecc ece ecr ecs ect eea eec eee eep eer ees eet ep- epa epc epe epp epr eps ept era erc ere erp err ers ert es- esa esc ese esp esr ess est eta etc ete etp etr ets ett p-p paa pac pae pap par pas pat pca pcc pce pcp pcr pcs pct pea pec pee pep per pes pet ppa ppc ppe ppp ppr pps ppt pra prc pre prp prr prs prt ps- psa psc pse psp psr pss pst pt- pta ptc pte ptp ptr pts ptt ra- raa rac rae rap rar ras rat rca rcc rce rcp rcr rcs rct re- rea rec ree rep rer res ret rpa rpc rpe rpp rpr rps rpt rra rrc rrp rrr rrs rrt rsa rsc rse rsp rsr rss rst rta rtc rte rtp rtr rts rtt saa sac sae sap sar sas sat sca scc sce scp scr scs sct se- sea sec see sep ser ses set spa spc spe spp spr sps spt sr- sra src sre srp srr srs srt ss- ssa ssc sse ssp ssr sss sst sta stc ste stp str sts stt taa tac tae tap tar tas tat tca tcc tce tcp tcr tcs tct te- tea tec tee tep ter tes tet tpa tpc tpe tpp tpr tps tpt tra trc tre trp trr trs trt tsa tsc tse tsp tsr tss tst tta ttc tte ttp ttr tts ttt