a-a aaa aaf aag aak aao aas af- afa aff afg afk afo afs ag- aga agf agg agk ago ags aka akg akk ako aks aoa aof aog aok aoo aos as- asa asf asg ask aso ass faa faf fag fak fao fas ffa fff ffg ffk ffo ffs fga fgf fgg fgs fka fkf fkg fkk foa fof fog fok foo fos fsa fsf fsg fsk fso fss gaa gaf gag gak gao gas gfa gff gfk gfo gfs gga ggg ggo ggs gka gko gks goa gof gog gok goo gos gsa gsf gsg gsk gso gss ka- kaa kaf kag kak kao kas kfa kff kfg kfo kfs kga kgf kgo kgs kkk kks koa kof kog kok koo kos ksa ksf ksg ksk kso kss oaa oaf oag oak oao oas of- ofa off ofg ofo ofs oga ogf ogg ogo ogs oka okg okk oko oks oo- ooa oof oog ook ooo oos os- osa osf osg osk oso oss saa saf sag sak sao sas sfa sff sfg sfk sfo sfs sga sgf sgg sgk sgo sgs sk- ska skf skg skk sko sks soa sof sog sok soo sos ss- ssa ssf ssg ssk sso sss