a-a aaa aaf aag aar aas af- afa aff afg afr afs ag- aga agf agg agr ags ar- ara arf arg arr ars as- asa asf asg asr ass faa faf fag far fas ffa fff ffg ffr ffs fga fgf fgg fgr fgs fra frf frg frr frs fsa fsf fsg fsr fss gaa gaf gag gar gas gfa gff gfr gfs gga ggg ggr ggs gra grf grg grr grs gsa gsf gsg gsr gss ra- raa raf rag rar ras rfa rff rfg rfr rfs rga rgf rgg rgr rgs rra rrf rrg rrr rrs rsa rsf rsg rsr rss saa saf sag sar sas sfa sff sfg sfr sfs sga sgf sgg sgr sgs sr- sra srf srg srr srs ss- ssa ssf ssg ssr sss