a-a a-b aaa aab aad aan aar aas ab- aba abb abd abn abr abs ad- ada adb add adn adr ads an- ana anb and ann anr ans ar- ara arb ard arn arr ars as- asa asb asd asn asr ass baa bab bad ban bar bas bba bbb bbd bbn bbr bbs bda bdb bdd bdr bds bna bnb bnd bnn bnr bns bra brb brd brn brr brs bsa bsb bsd bsn bsr bss daa dab dad dan dar das dba dbb dbd dbn dbr dbs dda ddb ddd ddn ddr dds dna dnb dnd dnn dnr dns dra drb drd drn drr drs dsa dsb dsd dsn dsr dss naa nab nad nan nar nas nba nbb nbd nbn nbr nbs nda ndb ndd ndn ndr nds nna nnb nnn nns nra nrb nrd nrn nrr nrs nsa nsb nsd nsn nsr nss ra- raa rab rad ran rar ras rba rbb rbd rbn rbr rbs rda rdb rdd rdn rdr rds rna rnb rnd rnn rnr rns rra rrb rrd rrn rrr rrs rsa rsb rsd rsn rsr rss saa sab sad san sar sas sba sbb sbd sbn sbr sbs sda sdb sdd sdn sdr sds sna snb snd snn snr sns sr- sra srb srd srn srr srs ss- ssa ssb ssd ssn ssr sss