a-a a-b a-c aaa aab aac aad aae aan ab- aba abb abc abd abe abn ac- aca acb acc acd ace acn ad- ada adb adc add ade adn aea aeb aec aed aee aen an- ana anb anc and ane ann baa bab bac bad bae ban bba bbb bbc bbd bbe bbn bca bcb bcc bcd bce bcn bda bdb bdc bdd bde be- bea beb bec bed bee ben bna bnb bnc bnd bne bnn c-- caa cab cac cad cae can cba cbb cbc cbd cbe cbn cca ccb ccc ccd cce ccn cda cdb cdc cdd cde cdn ce- cea ceb cec ced cee cen cn- cna cnb cnc cnd cne cnn daa dab dac dad dae dan dba dbb dbc dbd dbe dbn dca dcb dcc dcd dce dcn dda ddb ddc ddd dde ddn de- dea deb dec ded dee den dna dnb dnc dnd dne dnn eaa eab eac ead eae ean eba ebb ebc ebd ebe ebn ec- eca ecb ecc ecd ece ecn ed- eda edb edc edd ede edn eea eeb eec eed eee een en- ena enb enc end ene enn naa nab nac nad nae nan nba nbb nbc nbd nbe nbn nca ncb ncc ncd nce ncn nda ndb ndc ndd nde ndn ne- nea neb nec ned nee nen nna nnb nnc nne nnn