a-a a-b aaa aab aad aak aan aar ab- aba abb abd abk abn abr ad- ada adb add adk adn adr aka akb akd akk akn akr an- ana anb and ank ann anr ar- ara arb ard ark arn arr baa bab bad bak ban bar bba bbb bbd bbk bbn bbr bda bdb bdd bdk bdr bka bkb bkk bkn bkr bna bnb bnd bnk bnn bnr bra brb brd brk brn brr daa dab dad dak dan dar dba dbb dbd dbk dbn dbr dda ddb ddd ddk ddn ddr dka dkb dkk dkr dna dnb dnd dnk dnn dnr dra drb drd drk drn drr ka- kaa kab kad kak kan kar kba kbb kbd kbk kbn kbr kda kdb kdk kdr kkb kkk kkn kkr kn- kna knd knk knn knr kra krd krk krn krr naa nab nad nak nan nar nba nbb nbd nbk nbn nbr nda ndb ndd ndk ndn ndr nka nkk nkn nkr nna nnb nnk nnn nra nrb nrd nrk nrn nrr ra- raa rab rad rak ran rar rba rbb rbd rbk rbn rbr rda rdb rdd rdn rdr rkb rkk rna rnb rnd rnn rnr rra rrb rrd rrk rrn rrr