a-a a-b a-c aaa aab aac aae aam ab- aba abb abc abe abm ac- aca acb acc ace acm aea aeb aec aee aem ama amb amc ame amm baa bab bac bae bam bba bbb bbc bbe bbm bca bcb bcc bce bcm be- bea beb bec bee bem bma bmb bmc bme bmm c-- caa cab cac cae cam cba cbb cbc cbe cbm cca ccb ccc cce ccm ce- cea ceb cec cee cem cma cmb cmc cme cmm eaa eab eac eae eam eba ebb ebc ebe ebm ec- eca ecb ecc ece ecm eea eeb eec eee eem em- ema emb emc eme emm maa mab mac mae mam mba mbb mbc mbe mbm mc- mca mcb mcc mce mcm mea meb mec mee mem mma mmb mmc mme mmm