a-a a-c aaa aac aaf aag aas ac- aca acc acf acg acs af- afa afc aff afg afs ag- aga agc agf agg ags as- asa asc asf asg ass c-- caa cac caf cag cas cca ccc ccf ccg ccs cfa cfc cff cfg cfs cga cgc cgg cgs csa csc csf csg css faa fac faf fag fas fca fcc fcf fcg fcs ffa ffc fff ffg ffs fga fgc fgf fgg fgs fsa fsc fsf fsg fss gaa gac gaf gag gas gca gcc gcf gcg gcs gfa gfc gff gfs gga ggc ggg ggs gsa gsc gsf gsg gss saa sac saf sag sas sca scc scf scg scs sfa sfc sff sfg sfs sga sgc sgf sgg sgs ss- ssa ssc ssf ssg sss