-er a-a a-c aaa aac aad aae aap aar ac- aca acc acd ace acp acr ad- ada adc add ade adp adr aea aec aed aee aep aer ap- apa apc apd ape app apr ar- ara arc ard are arp arr c-- caa cac cad cae cap car cca ccc ccd cce ccp ccr cda cdc cdd cde cdp cdr ce- cea cec ced cee cep cer cpa cpc cpd cpe cpp cpr cra crc crd cre crp crr daa dac dad dae dap dar dca dcc dcd dce dcp dcr dda ddc ddd dde ddp ddr de- dea dec ded dee dep der dpa dpc dpd dpe dpp dpr dra drc drd dre drp drr eaa eac ead eae eap ear ec- eca ecc ecd ece ecr ed- eda edc edd ede edp edr eea eec eed eee eep eer ep- epa epc epd epe epp epr era erc erd ere erp err p-p paa pac pad pae pap par pca pcc pcd pce pcp pcr pda pdc pdd pde pdp pdr pea pec ped pee pep per ppa ppc ppd ppe ppp ppr pra prc prd pre prp prr ra- raa rac rad rae rap rar rca rcc rcd rce rcp rcr rda rdc rdd rde rdp rdr re- rea rec red ree rep rer rpa rpc rpd rpe rpp rpr rra rrc rrd rrp rrr