a-a a-i aaa aaf aag aai aas af- afa aff afg afi afs ag- aga agf agg agi ags ai- aia aif aig aii ais as- asa asf asg asi ass faa faf fag fai fas ffa fff ffg ffi ffs fga fgf fgg fgi fgs fia fif fig fii fis fsa fsf fsg fsi fss gaa gaf gag gai gas gfa gff gfi gfs gga ggg ggi ggs gia gif gig gii gis gsa gsf gsg gsi gss i-f ia- iaa iaf iag iai ias ifa iff ifg ifi ifs iga igf igg igi igs iia iif iii iis is- isa isf isg isi iss saa saf sag sai sas sfa sff sfg sfi sfs sga sgf sgg sgi sgs sia sif sig sii sis ss- ssa ssf ssg ssi sss