a-a a-c aaa aac aaf aak aao aar aas ac- aca acc acf ack aco acr acs af- afa afc aff afk afo afr afs aka akc akk ako akr aks aoa aoc aof aok aoo aor aos ar- ara arc arf ark aro arr ars as- asa asc asf ask aso asr ass c-- caa cac caf cak cao car cas cca ccc ccf cck cco ccr ccs cfa cfc cff cfk cfo cfr cfs cka ckc cko cks co- coa coc cof cok coo cor cos cra crc crf crk cro crr crs csa csc csf csk cso csr css faa fac faf fak fao far fas fca fcc fcf fck fco fcr fcs ffa ffc fff ffk ffo ffr ffs fka fkc fkf fkk foa foc fof fok foo for fos fra frc frf frk fro frr frs fsa fsc fsf fsk fso fsr fss ka- kaa kac kaf kak kao kar kas kca kcc kck kcr kcs kfa kfc kff kfo kfs kkc kkk kkr kks koa koc kof kok koo kor kos kra krc krf krk kro krr krs ksa ksc ksf ksk kso ksr kss oaa oac oaf oak oao oar oas oc- oca occ ocf ock oco ocr ocs of- ofa ofc off ofo ofr ofs oka okc okk oko okr oks oo- ooa ooc oof ook ooo oor oos or- ora orc orf ork oro orr ors os- osa osc osf osk oso osr oss ra- raa rac raf rak rao rar ras rca rcc rcf rco rcr rcs rfa rfc rff rfk rfo rfr rfs rkc rkf rkk rko rks roa roc rof rok roo ror ros rra rrc rrf rrk rrr rrs rsa rsc rsf rsk rso rsr rss saa sac saf sak sao sar sas sca scc scf sck sco scr scs sfa sfc sff sfk sfo sfr sfs sk- ska skc skf skk sko skr sks soa soc sof sok soo sor sos sr- sra src srf srk sro srr srs ss- ssa ssc ssf ssk sso ssr sss