-er a-a a-c aaa aac aae aao aap aar aas ac- aca acc ace aco acp acr acs aea aec aee aeo aep aer aes aoa aoc aoe aoo aop aor aos ap- apa apc ape apo app apr aps ar- ara arc are aro arp arr ars as- asa asc ase aso asp asr ass c-- caa cac cae cao cap car cas cca ccc cce cco ccp ccr ccs ce- cea cec cee ceo cep cer ces co- coa coc coe coo cop cor cos cpa cpc cpe cpo cpp cpr cps cra crc cre cro crp crr crs csa csc cse cso csp csr css eaa eac eae eao eap ear eas ec- eca ecc ece eco ecr ecs eea eec eee eeo eep eer ees eo- eoa eoc eoe eoo eop eor eos ep- epa epc epe epo epp epr eps era erc ere ero erp err ers es- esa esc ese eso esp esr ess oaa oac oae oao oap oar oas oc- oca occ oco ocp ocr ocs oea oec oee oeo oep oer oes oo- ooa ooc ooo oop oor oos op- opa opc ope opo opp opr ops or- ora orc ore oro orp orr ors os- osa osc ose oso osp osr oss p-p paa pac pae pao pap par pas pca pcc pce pco pcp pcr pcs pea pec pee peo pep per pes poa poc poe poo pop por pos ppa ppc ppe ppo ppp ppr pps pra prc pre pro prp prr prs ps- psa psc pse pso psp psr pss ra- raa rac rae rao rap rar ras rca rcc rce rco rcp rcr rcs re- rea rec ree reo rep rer res roa roc roe roo rop ror ros rpa rpc rpe rpo rpp rpr rps rra rrc rrp rrr rrs rsa rsc rse rso rsp rsr rss saa sac sae sao sap sar sas sca scc sce sco scp scr scs se- sea sec see seo sep ser ses soa soc soe soo sop sor sos spa spc spe spo spp spr sps sr- sra src sre sro srp srr srs ss- ssa ssc sse sso ssp ssr sss