a-a aaa aak aan aao aar aas aka akk akn ako akr aks an- ana ank ann ano anr ans aoa aok aon aoo aor aos ar- ara ark arn aro arr ars as- asa ask asn aso asr ass ka- kaa kak kan kao kar kas kkk kkn kkr kks kn- kna knk knn kno knr koa kok kon koo kor kos kra krk krn kro krr krs ksa ksk ksn kso ksr kss naa nak nan nao nar nas nka nkk nkn nko nkr nks nna nnk nnn nno nns no- noa nok non noo nor nos nra nrk nrn nro nrr nrs nsa nsk nsn nso nsr nss oaa oak oan oao oar oas oka okk oko okr oks on- ona onk onn ono onr ons oo- ooa ook oon ooo oor oos or- ora ork orn oro orr ors os- osa osk osn oso osr oss ra- raa rak ran rao rar ras rkk rko rks rna rnn rno rnr rns roa rok ron roo ror ros rra rrk rrn rrr rrs rsa rsk rsn rso rsr rss saa sak san sao sar sas sk- ska skk sko skr sks sna snk snn sno snr sns soa sok son soo sor sos sr- sra srk srn sro srr srs ss- ssa ssk ssn sso ssr sss