a-a a-c aaa aac aaf aag aan ac- aca acc acf acg acn af- afa afc aff afg afn ag- aga agc agf agg agn an- ana anc anf ang ann c-- caa cac caf cag can cca ccc ccf ccg ccn cfa cfc cff cfg cfn cga cgc cgg cgn cn- cna cnc cnf cng cnn faa fac faf fag fan fca fcc fcf fcg fcn ffa ffc fff ffg ffn fga fgc fgf fgg fgn fna fnc fnf fng fnn gaa gac gaf gag gan gca gcc gcf gcg gcn gfa gfc gff gga ggc ggg ggn gna gnc gnf gnn naa nac naf nag nan nca ncc ncf ncg ncn nfa nfc nff nfn nga ngc ngf ngg ngn nna nnc nnf nng nnn