a-a a-b aaa aab aae aak aam aan ab- aba abb abe abk abm abn aea aeb aee aek aem aen aka akb ake akk akm akn ama amb ame amk amm amn an- ana anb ane ank anm ann baa bab bae bak bam ban bba bbb bbe bbk bbm bbn be- bea beb bee bek bem ben bka bkb bke bkk bkm bkn bma bmb bme bmk bmm bmn bna bnb bne bnk bnn eaa eab eae eak eam ean eba ebb ebe ebk ebm ebn eea eeb eee eek eem een eka ekb eke em- ema emb eme emk emm emn en- ena enb ene enk enm enn ka- kaa kab kae kak kam kan kba kbb kbe kbk kbm kbn ke- kea keb kee kek kem ken kkb kke kkk kkm kkn kma kmb kme kmk kmm kn- kna kne knk knm knn maa mab mae mak mam man mba mbb mbe mbk mbm mea meb mee mek mem men mka mkb mke mkk mkm mkn mma mmb mme mmk mmm mmn mna mnb mne mnk mnm mnn naa nab nae nak nam nan nba nbb nbe nbk nbm nbn ne- nea neb nee nek nem nen nka nke nkk nkm nkn nma nmb nme nmk nmm nmn nna nnb nne nnk nnm nnn