a-a a-b aaa aab aae aak aam ab- aba abb abe abk abm aea aeb aee aek aem aka akb ake akk akm ama amb ame amk amm baa bab bae bak bam bba bbb bbe bbk bbm be- bea beb bee bek bem bka bkb bke bkk bkm bma bmb bme bmk bmm eaa eab eae eak eam eba ebb ebe ebk ebm eea eeb eee eek eem eka ekb eke em- ema emb eme emk emm ka- kaa kab kae kak kam kba kbb kbe kbk kbm ke- kea keb kee kek kem kkb kke kkk kkm kma kmb kme kmk kmm maa mab mae mak mam mba mbb mbe mbk mbm mea meb mee mek mem mka mkb mke mkk mkm mma mmb mme mmk mmm