-er a-a a-c aaa aac aae aaf aap aar ac- aca acc ace acf acp acr aea aec aee aef aep aer af- afa afc afe aff afp afr ap- apa apc ape apf app apr ar- ara arc are arf arp arr c-- caa cac cae caf cap car cca ccc cce ccf ccp ccr ce- cea cec cee cef cep cer cfa cfc cfe cff cfp cfr cpa cpc cpe cpf cpp cpr cra crc cre crf crp crr eaa eac eae eaf eap ear ec- eca ecc ece ecf ecr eea eec eee eef eep eer ef- efa efc efe eff efp efr ep- epa epc epe epf epp epr era erc ere erf erp err faa fac fae faf fap far fca fcc fce fcf fcp fcr fea fec fee fef fep fer ffa ffc ffe fff ffp ffr fpa fpc fpe fpp fpr fra frc fre frf frp frr p-p paa pac pae paf pap par pca pcc pce pcf pcp pcr pea pec pee pef pep per pfa pfc pfe pff pfp pfr ppa ppc ppe ppf ppp ppr pra prc pre prf prp prr ra- raa rac rae raf rap rar rca rcc rce rcf rcp rcr re- rea rec ree ref rep rer rfa rfc rfe rff rfp rfr rpa rpc rpe rpf rpp rpr rra rrc rrf rrp rrr