a-a aaa aaf aag aao aar aas af- afa aff afg afo afr afs ag- aga agf agg ago agr ags aoa aof aog aoo aor aos ar- ara arf arg aro arr ars as- asa asf asg aso asr ass faa faf fag fao far fas ffa fff ffg ffo ffr ffs fga fgf fgg fgr fgs foa fof fog foo for fos fra frf frg fro frr frs fsa fsf fsg fso fsr fss gaa gaf gag gao gar gas gfa gff gfo gfr gfs gga ggg ggo ggr ggs goa gof gog goo gor gos gra grf grg gro grr grs gsa gsf gsg gso gsr gss oaa oaf oag oao oar oas of- ofa off ofg ofo ofr ofs oga ogf ogg ogo ogs oo- ooa oof oog ooo oor oos or- ora orf org oro orr ors os- osa osf osg oso osr oss ra- raa raf rag rao rar ras rfa rff rfg rfo rfr rfs rga rgf rgg rgo rgr rgs roa rof rog roo ror ros rra rrf rrg rrr rrs rsa rsf rsg rso rsr rss saa saf sag sao sar sas sfa sff sfg sfo sfr sfs sga sgf sgg sgo sgr sgs soa sof sog soo sor sos sr- sra srf srg sro srr srs ss- ssa ssf ssg sso ssr sss