-er a-a a-c a-t aaa aac aae aap aar aat ac- aca acc ace acp acr act aea aec aee aep aer aet ap- apa apc ape app apr apt ar- ara arc are arp arr art at- ata atc ate atp atr att c-- caa cac cae cap car cat cca ccc cce ccp ccr cct ce- cea cec cee cep cer cet cpa cpc cpe cpp cpr cpt cra crc cre crp crr crt cta ctc cte ctp ctr ctt eaa eac eae eap ear eat ec- eca ecc ece ecr ect eea eec eee eep eer eet ep- epa epc epe epp epr ept era erc ere erp err ert eta etc ete etp etr ett p-p paa pac pae pap par pat pca pcc pce pcp pcr pct pea pec pee pep per pet ppa ppc ppe ppp ppr ppt pra prc pre prp prr prt pt- pta ptc pte ptp ptr ptt ra- raa rac rae rap rar rat rca rcc rce rcp rcr rct re- rea rec ree rep rer ret rpa rpc rpe rpp rpr rpt rra rrc rrp rrr rrt rta rtc rte rtp rtr rtt taa tac tae tap tar tat tca tcc tce tcp tcr tct te- tea tec tee tep ter tet tpa tpc tpe tpp tpr tpt tra trc tre trp trr trt tta ttc tte ttp ttr ttt