-er a-a a-c aaa aac aae aaf aap aar aas ac- aca acc ace acf acp acr acs aea aec aee aef aep aer aes af- afa afc afe aff afp afr afs ap- apa apc ape apf app apr aps ar- ara arc are arf arp arr ars as- asa asc ase asf asp asr ass c-- caa cac cae caf cap car cas cca ccc cce ccf ccp ccr ccs ce- cea cec cee cef cep cer ces cfa cfc cfe cff cfp cfr cfs cpa cpc cpe cpf cpp cpr cps cra crc cre crf crp crr crs csa csc cse csf csp csr css eaa eac eae eaf eap ear eas ec- eca ecc ece ecf ecr ecs eea eec eee eef eep eer ees ef- efa efc efe eff efp efr efs ep- epa epc epe epf epp epr eps era erc ere erf erp err ers es- esa esc ese esf esp esr ess faa fac fae faf fap far fas fca fcc fce fcf fcp fcr fcs fea fec fee fef fep fer fes ffa ffc ffe fff ffp ffr ffs fpa fpc fpe fpp fpr fps fra frc fre frf frp frr frs fsa fsc fse fsf fsp fsr fss p-p paa pac pae paf pap par pas pca pcc pce pcf pcp pcr pcs pea pec pee pef pep per pes pfa pfc pfe pff pfp pfr pfs ppa ppc ppe ppf ppp ppr pps pra prc pre prf prp prr prs ps- psa psc pse psf psp psr pss ra- raa rac rae raf rap rar ras rca rcc rce rcf rcp rcr rcs re- rea rec ree ref rep rer res rfa rfc rfe rff rfp rfr rfs rpa rpc rpe rpf rpp rpr rps rra rrc rrf rrp rrr rrs rsa rsc rse rsf rsp rsr rss saa sac sae saf sap sar sas sca scc sce scf scp scr scs se- sea sec see sef sep ser ses sfa sfc sfe sff sfp sfr sfs spa spc spe spf spp spr sps sr- sra src sre srf srp srr srs ss- ssa ssc sse ssf ssp ssr sss