-er a-a a-c aaa aac aae aao aar aas ac- aca acc ace aco acr acs aea aec aee aeo aer aes aoa aoc aoe aoo aor aos ar- ara arc are aro arr ars as- asa asc ase aso asr ass c-- caa cac cae cao car cas cca ccc cce cco ccr ccs ce- cea cec cee ceo cer ces co- coa coc coe coo cor cos cra crc cre cro crr crs csa csc cse cso csr css eaa eac eae eao ear eas ec- eca ecc ece eco ecr ecs eea eec eee eeo eer ees eo- eoa eoc eoe eoo eor eos era erc ere ero err ers es- esa esc ese eso esr ess oaa oac oae oao oar oas oc- oca occ oco ocr ocs oea oec oee oeo oer oes oo- ooa ooc ooo oor oos or- ora orc ore oro orr ors os- osa osc ose oso osr oss ra- raa rac rae rao rar ras rca rcc rce rco rcr rcs re- rea rec ree reo rer res roa roc roe roo ror ros rra rrc rrr rrs rsa rsc rse rso rsr rss saa sac sae sao sar sas sca scc sce sco scr scs se- sea sec see seo ser ses soa soc soe soo sor sos sr- sra src sre sro srr srs ss- ssa ssc sse sso ssr sss