-er a-a a-c aaa aac aae aaf aag aan aar ac- aca acc ace acf acg acn acr aea aec aee aef aeg aen aer af- afa afc afe aff afg afn afr ag- aga agc age agf agg agn agr an- ana anc ane anf ang ann anr ar- ara arc are arf arg arn arr c-- caa cac cae caf cag can car cca ccc cce ccf ccg ccn ccr ce- cea cec cee cef ceg cen cer cfa cfc cfe cff cfg cfn cfr cga cgc cge cgg cgn cgr cn- cna cnc cne cnf cng cnn cnr cra crc cre crf crg crn crr eaa eac eae eaf eag ean ear ec- eca ecc ece ecf ecg ecn ecr eea eec eee eef eeg een eer ef- efa efc efe eff efg efr ega egc ege egf egg egn egr en- ena enc ene enf eng enn enr era erc ere erf erg ern err faa fac fae faf fag fan far fca fcc fce fcf fcg fcn fcr fea fec fee fef feg fen fer ffa ffc ffe fff ffg ffn ffr fga fgc fge fgf fgg fgn fgr fna fnc fne fnf fng fnn fnr fra frc fre frf frg frn frr gaa gac gae gaf gag gan gar gca gcc gce gcf gcg gcn gcr ge- gea gec gee gef geg gen ger gfa gfc gfe gff gfr gga ggc ggg ggn ggr gna gnc gne gnf gnn gnr gra grc gre grf grg grn grr naa nac nae naf nag nan nar nca ncc nce ncf ncg ncn ncr ne- nea nec nee nef neg nen ner nfa nfc nfe nff nfn nfr nga ngc nge ngf ngg ngn nna nnc nne nnf nng nnn nra nrc nre nrf nrg nrn nrr ra- raa rac rae raf rag ran rar rca rcc rce rcf rcg rcn rcr re- rea rec ree ref reg ren rer rfa rfc rfe rff rfg rfn rfr rga rgc rge rgf rgg rgn rgr rna rnc rng rnn rnr rra rrc rrf rrg rrn rrr