a-a a-b a-t aaa aab aad aaf aan aao aas aat ab- aba abb abd abf abn abo abs abt ad- ada adb add adf adn ado ads adt af- afa afb afd aff afn afo afs aft an- ana anb and anf ann ano ans ant aoa aob aod aof aon aoo aos aot as- asa asb asd asf asn aso ass ast at- ata atb atd atf atn ato ats att baa bab bad baf ban bao bas bat bba bbb bbd bbf bbn bbo bbs bbt bda bdb bdd bdf bdo bds bdt bfa bfb bfd bff bfn bfo bfs bft bna bnb bnd bnf bnn bno bns bnt boa bob bod bof bon boo bos bot bsa bsb bsd bsf bsn bso bss bst bta btb btd btf btn bto bts btt daa dab dad daf dan dao das dat dba dbb dbd dbf dbn dbo dbs dbt dda ddb ddd ddf ddn ddo dds ddt dfa dfb dfd dff dfn dfo dfs dft dna dnb dnd dnf dnn dno dns dnt doa dob dod dof don doo dos dot dsa dsb dsd dsf dsn dso dss dst dta dtb dtd dtf dtn dto dts dtt faa fab fad faf fan fao fas fat fba fbb fbd fbf fbn fbo fbs fbt fda fdb fdd fdf fdn fdo fds fdt ffa ffd fff ffn ffo ffs fft fna fnb fnd fnf fnn fns fnt foa fob fof fon foo fos fot fsa fsb fsd fsf fsn fso fss fst fta ftb ftd ftf ftn fto fts ftt naa nab nad naf nan nao nas nat nba nbb nbd nbf nbn nbo nbs nbt nda ndb ndd ndf ndn ndo nds ndt nfa nfb nfd nff nfn nfo nfs nft nna nnb nnf nnn nno nns nnt no- noa nob nod nof non noo nos not nsa nsb nsd nsf nsn nso nss nst nta ntb ntd ntf ntn nto nts ntt oaa oab oad oaf oan oao oas oat ob- oba obb obd obf obn obo obs obt oda odb odd odf odn odo ods odt of- ofa ofb ofd off ofn ofo ofs oft on- ona onb ond onf onn ono ons ont oo- ooa oob ood oof oon ooo oos oot os- osa osb osd osf osn oso oss ost ot- ota otb otd otf otn oto ots ott saa sab sad saf san sao sas sat sba sbb sbd sbf sbn sbo sbs sbt sda sdb sdd sdf sdn sdo sds sdt sfa sfb sfd sff sfn sfo sfs sft sna snb snd snf snn sno sns snt soa sob sod sof son soo sos sot ss- ssa ssb ssd ssf ssn sso sss sst sta stb std stf stn sto sts stt taa tab tad taf tan tao tas tat tba tbb tbd tbf tbn tbo tbs tbt tda tdb tdd tdf tdn tdo tds tdt tfa tfb tfd tff tfn tfo tfs tft tna tnb tnd tnf tnn tno tns tnt to- toa tob tod tof ton too tos tot tsa tsb tsd tsf tsn tso tss tst tta ttb ttd ttf ttn tto tts ttt