a-a a-b a-c aaa aab aac aae aah ab- aba abb abc abe abh ac- aca acb acc ace ach aea aeb aec aee aeh aha ahb ahc ahe ahh baa bab bac bae bah bba bbb bbc bbe bbh bca bcb bcc bce bch be- bea beb bec bee beh bha bhb bhc bhe bhh c-- caa cab cac cae cah cba cbb cbc cbe cbh cca ccb ccc cce cch ce- cea ceb cec cee ceh ch- cha chb chc che chh eaa eab eac eae eah eba ebb ebc ebe ebh ec- eca ecb ecc ece ech eea eeb eec eee eha ehb ehc ehe ehh haa hab hac hae hah hba hbb hbc hbe hbh hca hcb hcc hce hch he- hea heb hec hee heh hha hhb hhc hhe hhh