a-a a-b a-t aaa aab aaf aag aao aas aat ab- aba abb abf abg abo abs abt af- afa afb aff afg afo afs aft ag- aga agb agf agg ago ags agt aoa aob aof aog aoo aos aot as- asa asb asf asg aso ass ast at- ata atb atf atg ato ats att baa bab baf bag bao bas bat bba bbb bbf bbg bbo bbs bbt bfa bfb bff bfg bfo bfs bft bga bgb bgf bgg bgo bgs bgt boa bob bof bog boo bos bot bsa bsb bsf bsg bso bss bst bta btb btf btg bto bts btt faa fab faf fag fao fas fat fba fbb fbf fbg fbo fbs fbt ffa fff ffg ffo ffs fft fga fgb fgf fgg fgs fgt foa fob fof fog foo fos fot fsa fsb fsf fsg fso fss fst fta ftb ftf ftg fto fts ftt gaa gab gaf gag gao gas gat gba gbf gbg gbo gbs gbt gfa gfb gff gfo gfs gft gga ggb ggg ggo ggs ggt goa gob gof gog goo gos got gsa gsb gsf gsg gso gss gst gta gtb gtf gtg gto gts gtt oaa oab oaf oag oao oas oat ob- oba obb obf obg obo obs obt of- ofa ofb off ofg ofo ofs oft oga ogf ogg ogo ogs ogt oo- ooa oob oof oog ooo oos oot os- osa osb osf osg oso oss ost ot- ota otb otf otg oto ots ott saa sab saf sag sao sas sat sba sbb sbf sbg sbo sbs sbt sfa sfb sff sfg sfo sfs sft sga sgb sgf sgg sgo sgs sgt soa sob sof sog soo sos sot ss- ssa ssb ssf ssg sso sss sst sta stb stf stg sto sts stt taa tab taf tag tao tas tat tba tbb tbf tbg tbo tbs tbt tfa tfb tff tfg tfo tfs tft tga tgb tgf tgg tgo tgs tgt to- toa tob tof tog too tos tot tsa tsb tsf tsg tso tss tst tta ttb ttf ttg tto tts ttt