a-a a-b aaa aab aad aak aan aas ab- aba abb abd abk abn abs ad- ada adb add adk adn ads aka akb akd akk akn aks an- ana anb and ank ann ans as- asa asb asd ask asn ass baa bab bad bak ban bas bba bbb bbd bbk bbn bbs bda bdb bdd bdk bds bka bkb bkk bkn bks bna bnb bnd bnk bnn bns bsa bsb bsd bsk bsn bss daa dab dad dak dan das dba dbb dbd dbk dbn dbs dda ddb ddd ddk ddn dds dka dkb dkk dks dna dnb dnd dnk dnn dns dsa dsb dsd dsk dsn dss ka- kaa kab kad kak kan kas kba kbb kbd kbk kbn kbs kda kdb kdk kds kkb kkk kkn kks kn- kna knd knk knn ksa ksb ksd ksk ksn kss naa nab nad nak nan nas nba nbb nbd nbk nbn nbs nda ndb ndd ndk ndn nds nka nkk nkn nks nna nnb nnk nnn nns nsa nsb nsd nsk nsn nss saa sab sad sak san sas sba sbb sbd sbk sbn sbs sda sdb sdd sdk sdn sds sk- ska skb skd skk sks sna snb snd snk snn sns ss- ssa ssb ssd ssk ssn sss