a-a a-b a-c aaa aab aac aah aan ab- aba abb abc abh abn ac- aca acb acc ach acn aha ahb ahc ahh ahn an- ana anb anc anh ann baa bab bac bah ban bba bbb bbc bbh bbn bca bcb bcc bch bcn bha bhb bhc bhh bna bnb bnc bnn c-- caa cab cac cah can cba cbb cbc cbh cbn cca ccb ccc cch ccn ch- cha chb chc chh chn cn- cna cnb cnc cnh cnn haa hab hac hah han hba hbb hbc hbh hbn hca hcb hcc hch hcn hha hhb hhc hhh hhn hna hnb hnc hnh hnn naa nab nac nah nan nba nbb nbc nbn nca ncb ncc nch ncn nha nhb nhc nhh nhn nna nnb nnc nnh nnn