a-a a-t aaa aaf aag aao aas aat af- afa aff afg afo afs aft ag- aga agf agg ago ags agt aoa aof aog aoo aos aot as- asa asf asg aso ass ast at- ata atf atg ato ats att faa faf fag fao fas fat ffa fff ffg ffo ffs fft fga fgf fgg fgs fgt foa fof fog foo fos fot fsa fsf fsg fso fss fst fta ftf ftg fto fts ftt gaa gaf gag gao gas gat gfa gff gfo gfs gft gga ggg ggo ggs ggt goa gof gog goo gos got gsa gsf gsg gso gss gst gta gtf gtg gto gts gtt oaa oaf oag oao oas oat of- ofa off ofg ofo ofs oft oga ogf ogg ogo ogs ogt oo- ooa oof oog ooo oos oot os- osa osf osg oso oss ost ot- ota otf otg oto ots ott saa saf sag sao sas sat sfa sff sfg sfo sfs sft sga sgf sgg sgo sgs sgt soa sof sog soo sos sot ss- ssa ssf ssg sso sss sst sta stf stg sto sts stt taa taf tag tao tas tat tfa tff tfg tfo tfs tft tga tgf tgg tgo tgs tgt to- toa tof tog too tos tot tsa tsf tsg tso tss tst tta ttf ttg tto tts ttt