a-a a-c aaa aac aaf aak aan aao aar aas ac- aca acc acf ack acn aco acr acs af- afa afc aff afk afn afo afr afs aka akc akk akn ako akr aks an- ana anc anf ank ann ano anr ans aoa aoc aof aok aon aoo aor aos ar- ara arc arf ark arn aro arr ars as- asa asc asf ask asn aso asr ass c-- caa cac caf cak can cao car cas cca ccc ccf cck ccn cco ccr ccs cfa cfc cff cfk cfn cfo cfr cfs cka ckc cko cks cn- cna cnc cnf cnn cno cnr cns co- coa coc cof cok con coo cor cos cra crc crf crk crn cro crr crs csa csc csf csk csn cso csr css faa fac faf fak fan fao far fas fca fcc fcf fck fcn fco fcr fcs ffa ffc fff ffk ffn ffo ffr ffs fka fkc fkf fkk fna fnc fnf fnk fnn fnr fns foa foc fof fok fon foo for fos fra frc frf frk frn fro frr frs fsa fsc fsf fsk fsn fso fsr fss ka- kaa kac kaf kak kan kao kar kas kca kcc kck kcn kcr kcs kfa kfc kff kfo kfs kkc kkk kkn kkr kks kn- kna knc knf knk knn kno knr koa koc kof kok kon koo kor kos kra krc krf krk krn kro krr krs ksa ksc ksf ksk ksn kso ksr kss naa nac naf nak nan nao nar nas nca ncc ncf nck ncn nco ncr ncs nfa nfc nff nfk nfn nfo nfr nfs nka nkc nkf nkk nkn nko nkr nks nna nnc nnf nnk nnn nno nns no- noa noc nof nok non noo nor nos nra nrc nrf nrk nrn nro nrr nrs nsa nsc nsf nsk nsn nso nsr nss oaa oac oaf oak oan oao oar oas oc- oca occ ocf ock ocn oco ocr ocs of- ofa ofc off ofn ofo ofr ofs oka okc okk oko okr oks on- ona onc onf onk onn ono onr ons oo- ooa ooc oof ook oon ooo oor oos or- ora orc orf ork orn oro orr ors os- osa osc osf osk osn oso osr oss ra- raa rac raf rak ran rao rar ras rca rcc rcf rcn rco rcr rcs rfa rfc rff rfk rfn rfo rfr rfs rkc rkf rkk rko rks rna rnc rnn rno rnr rns roa roc rof rok ron roo ror ros rra rrc rrf rrk rrn rrr rrs rsa rsc rsf rsk rsn rso rsr rss saa sac saf sak san sao sar sas sca scc scf sck scn sco scr scs sfa sfc sff sfk sfn sfo sfr sfs sk- ska skc skf skk sko skr sks sna snc snf snk snn sno snr sns soa soc sof sok son soo sor sos sr- sra src srf srk srn sro srr srs ss- ssa ssc ssf ssk ssn sso ssr sss