a-a a-c aaa aac aad aak aao aar ac- aca acc acd ack aco acr ad- ada adc add adk ado adr aka akc akd akk ako akr aoa aoc aod aok aoo aor ar- ara arc ard ark aro arr c-- caa cac cad cak cao car cca ccc ccd cck cco ccr cda cdc cdd cdk cdo cdr cka ckc ckd cko co- coa coc cod cok coo cor cra crc crd crk cro crr daa dac dad dak dao dar dca dcc dcd dck dco dcr dda ddc ddd ddk ddo ddr dka dkc dkk dko dkr doa doc dod dok doo dor dra drc drd drk dro drr ka- kaa kac kad kak kao kar kca kcc kcd kck kcr kda kdc kdk kdo kdr kkc kkk kkr koa koc kod kok koo kor kra krc krd krk kro krr oaa oac oad oak oao oar oc- oca occ ocd ock oco ocr oda odc odd odo odr oka okc okd okk oko okr oo- ooa ooc ood ook ooo oor or- ora orc ord ork oro orr ra- raa rac rad rak rao rar rca rcc rcd rco rcr rda rdc rdd rdo rdr rkc rkk rko roa roc rod rok roo ror rra rrc rrd rrk rrr