a-a a-b aaa aab aae aag aam aan ab- aba abb abe abg abm abn aea aeb aee aeg aem aen ag- aga agb age agg agm agn ama amb ame amg amm amn an- ana anb ane ang anm ann baa bab bae bag bam ban bba bbb bbe bbg bbm bbn be- bea beb bee beg bem ben bga bgb bge bgg bgm bgn bma bmb bme bmg bmm bmn bna bnb bne bng bnn eaa eab eae eag eam ean eba ebb ebe ebg ebm ebn eea eeb eee eeg eem een ega egb ege egg egm egn em- ema emb eme emg emm emn en- ena enb ene eng enm enn gaa gab gae gag gam gan gba gbe gbg gbm gbn ge- gea geb gee geg gem gen gga ggb ggg ggm ggn gma gmb gme gmg gmm gmn gna gnb gne gnm gnn maa mab mae mag mam man mba mbb mbe mbg mbm mea meb mee meg mem men mga mgb mge mgm mgn mma mmb mme mmg mmm mmn mna mnb mne mng mnm mnn naa nab nae nag nam nan nba nbb nbe nbg nbm nbn ne- nea neb nee neg nem nen nga ngb nge ngg ngm ngn nma nmb nme nmg nmm nmn nna nnb nne nng nnm nnn