-er a-a a-c aaa aac aad aae aar ac- aca acc acd ace acr ad- ada adc add ade adr aea aec aed aee aer ar- ara arc ard are arr c-- caa cac cad cae car cca ccc ccd cce ccr cda cdc cdd cde cdr ce- cea cec ced cee cer cra crc crd cre crr daa dac dad dae dar dca dcc dcd dce dcr dda ddc ddd dde ddr de- dea dec ded dee der dra drc drd dre drr eaa eac ead eae ear ec- eca ecc ecd ece ecr ed- eda edc edd ede edr eea eec eed eee eer era erc erd ere err ra- raa rac rad rae rar rca rcc rcd rce rcr rda rdc rdd rde rdr re- rea rec red ree rer rra rrc rrd rrr