a-a a-b a-t aaa aab aad aan aas aat ab- aba abb abd abn abs abt ad- ada adb add adn ads adt an- ana anb and ann ans ant as- asa asb asd asn ass ast at- ata atb atd atn ats att baa bab bad ban bas bat bba bbb bbd bbn bbs bbt bda bdb bdd bds bdt bna bnb bnd bnn bns bnt bsa bsb bsd bsn bss bst bta btb btd btn bts btt daa dab dad dan das dat dba dbb dbd dbn dbs dbt dda ddb ddd ddn dds ddt dna dnb dnd dnn dns dnt dsa dsb dsd dsn dss dst dta dtb dtd dtn dts dtt naa nab nad nan nas nat nba nbb nbd nbn nbs nbt nda ndb ndd ndn nds ndt nna nnb nnn nns nnt nsa nsb nsd nsn nss nst nta ntb ntd ntn nts ntt saa sab sad san sas sat sba sbb sbd sbn sbs sbt sda sdb sdd sdn sds sdt sna snb snd snn sns snt ss- ssa ssb ssd ssn sss sst sta stb std stn sts stt taa tab tad tan tas tat tba tbb tbd tbn tbs tbt tda tdb tdd tdn tds tdt tna tnb tnd tnn tns tnt tsa tsb tsd tsn tss tst tta ttb ttd ttn tts ttt