a-a a-b a-c aaa aab aac aae aak aam ab- aba abb abc abe abk abm ac- aca acb acc ace ack acm aea aeb aec aee aek aem aka akb akc ake akk akm ama amb amc ame amk amm baa bab bac bae bak bam bba bbb bbc bbe bbk bbm bca bcb bcc bce bck bcm be- bea beb bec bee bek bem bka bkb bkc bke bkk bkm bma bmb bmc bme bmk bmm c-- caa cab cac cae cak cam cba cbb cbc cbe cbk cbm cca ccb ccc cce cck ccm ce- cea ceb cec cee cek cem cka ckb ckc ckm cma cmb cmc cme cmk cmm eaa eab eac eae eak eam eba ebb ebc ebe ebk ebm ec- eca ecb ecc ece eck ecm eea eeb eec eee eek eem eka ekb ekc eke em- ema emb emc eme emk emm ka- kaa kab kac kae kak kam kba kbb kbc kbe kbk kbm kca kcb kcc kce kck kcm ke- kea keb kec kee kek kem kkb kkc kke kkk kkm kma kmb kmc kme kmk kmm maa mab mac mae mak mam mba mbb mbc mbe mbk mbm mc- mca mcb mcc mce mck mcm mea meb mec mee mek mem mka mkb mkc mke mkk mkm mma mmb mmc mme mmk mmm