a-a a-b aaa aab aad aak aan aao aas ab- aba abb abd abk abn abo abs ad- ada adb add adk adn ado ads aka akb akd akk akn ako aks an- ana anb and ank ann ano ans aoa aob aod aok aon aoo aos as- asa asb asd ask asn aso ass baa bab bad bak ban bao bas bba bbb bbd bbk bbn bbo bbs bda bdb bdd bdk bdo bds bka bkb bkk bkn bko bks bna bnb bnd bnk bnn bno bns boa bob bod bok bon boo bos bsa bsb bsd bsk bsn bso bss daa dab dad dak dan dao das dba dbb dbd dbk dbn dbo dbs dda ddb ddd ddk ddn ddo dds dka dkb dkk dko dks dna dnb dnd dnk dnn dno dns doa dob dod dok don doo dos dsa dsb dsd dsk dsn dso dss ka- kaa kab kad kak kan kao kas kba kbb kbd kbk kbn kbo kbs kda kdb kdk kdo kds kkb kkk kkn kks kn- kna knd knk knn kno koa kob kod kok kon koo kos ksa ksb ksd ksk ksn kso kss naa nab nad nak nan nao nas nba nbb nbd nbk nbn nbo nbs nda ndb ndd ndk ndn ndo nds nka nkk nkn nko nks nna nnb nnk nnn nno nns no- noa nob nod nok non noo nos nsa nsb nsd nsk nsn nso nss oaa oab oad oak oan oao oas ob- oba obb obd obk obn obo obs oda odb odd odn odo ods oka okb okd okk oko oks on- ona onb ond onk onn ono ons oo- ooa oob ood ook oon ooo oos os- osa osb osd osk osn oso oss saa sab sad sak san sao sas sba sbb sbd sbk sbn sbo sbs sda sdb sdd sdk sdn sdo sds sk- ska skb skd skk sko sks sna snb snd snk snn sno sns soa sob sod sok son soo sos ss- ssa ssb ssd ssk ssn sso sss