a-a a-c aaa aac aae aaf aag aan ac- aca acc ace acf acg acn aea aec aee aef aeg aen af- afa afc afe aff afg afn ag- aga agc age agf agg agn an- ana anc ane anf ang ann c-- caa cac cae caf cag can cca ccc cce ccf ccg ccn ce- cea cec cee cef ceg cen cfa cfc cfe cff cfg cfn cga cgc cge cgg cgn cn- cna cnc cne cnf cng cnn eaa eac eae eaf eag ean ec- eca ecc ece ecf ecg ecn eea eec eee eef eeg een ef- efa efc efe eff efg ega egc ege egf egg egn en- ena enc ene enf eng enn faa fac fae faf fag fan fca fcc fce fcf fcg fcn fea fec fee fef feg fen ffa ffc ffe fff ffg ffn fga fgc fge fgf fgg fgn fna fnc fne fnf fng fnn gaa gac gae gaf gag gan gca gcc gce gcf gcg gcn ge- gea gec gee gef geg gen gfa gfc gfe gff gga ggc ggg ggn gna gnc gne gnf gnn naa nac nae naf nag nan nca ncc nce ncf ncg ncn ne- nea nec nee nef neg nen nfa nfc nfe nff nfn nga ngc nge ngf ngg ngn nna nnc nne nnf nng nnn