-er a-a a-b aaa aab aae aam aan aar ab- aba abb abe abm abn abr aea aeb aee aem aen aer ama amb ame amm amn amr an- ana anb ane anm ann anr ar- ara arb are arm arn arr baa bab bae bam ban bar bba bbb bbe bbm bbn bbr be- bea beb bee bem ben ber bma bmb bme bmm bmn bmr bna bnb bne bnn bnr bra brb bre brm brn brr eaa eab eae eam ean ear eba ebb ebe ebm ebn ebr eea eeb eee eem een eer em- ema emb eme emm emn emr en- ena enb ene enm enn enr era erb ere erm ern err m-r maa mab mae mam man mar mba mbb mbe mbm mbr mea meb mee mem men mer mma mmb mme mmm mmn mmr mna mnb mne mnm mnn mnr mra mrb mre mrm mrn mrr naa nab nae nam nan nar nba nbb nbe nbm nbn nbr ne- nea neb nee nem nen ner nma nmb nme nmm nmn nmr nna nnb nne nnm nnn nra nrb nre nrm nrn nrr ra- raa rab rae ram ran rar rba rbb rbe rbm rbn rbr re- rea reb ree rem ren rer rma rmb rme rmm rmn rmr rna rnb rnm rnn rnr rra rrb rrm rrn rrr