a-a a-c aaa aac aad aao aar ac- aca acc acd aco acr ad- ada adc add ado adr aoa aoc aod aoo aor ar- ara arc ard aro arr c-- caa cac cad cao car cca ccc ccd cco ccr cda cdc cdd cdo cdr co- coa coc cod coo cor cra crc crd cro crr daa dac dad dao dar dca dcc dcd dco dcr dda ddc ddd ddo ddr doa doc dod doo dor dra drc drd dro drr oaa oac oad oao oar oc- oca occ ocd oco ocr oda odc odd odo odr oo- ooa ooc ood ooo oor or- ora orc ord oro orr ra- raa rac rad rao rar rca rcc rcd rco rcr rda rdc rdd rdo rdr roa roc rod roo ror rra rrc rrd rrr