a-a a-b a-c aaa aab aac aae aam aan ab- aba abb abc abe abm abn ac- aca acb acc ace acm acn aea aeb aec aee aem aen ama amb amc ame amm amn an- ana anb anc ane anm ann baa bab bac bae bam ban bba bbb bbc bbe bbm bbn bca bcb bcc bce bcm bcn be- bea beb bec bee bem ben bma bmb bmc bme bmm bmn bna bnb bnc bne bnn c-- caa cab cac cae cam can cba cbb cbc cbe cbm cbn cca ccb ccc cce ccm ccn ce- cea ceb cec cee cem cen cma cmb cmc cme cmm cmn cn- cna cnb cnc cne cnm cnn eaa eab eac eae eam ean eba ebb ebc ebe ebm ebn ec- eca ecb ecc ece ecm ecn eea eeb eec eee eem een em- ema emb emc eme emm emn en- ena enb enc ene enm enn maa mab mac mae mam man mba mbb mbc mbe mbm mc- mca mcb mcc mce mcm mcn mea meb mec mee mem men mma mmb mmc mme mmm mmn mna mnb mnc mne mnm mnn naa nab nac nae nam nan nba nbb nbc nbe nbm nbn nca ncb ncc nce ncm ncn ne- nea neb nec nee nem nen nma nmb nmc nme nmm nmn nna nnb nnc nne nnm nnn