a-a a-b a-c aaa aab aac aae aag aao ab- aba abb abc abe abg abo ac- aca acb acc ace acg aco aea aeb aec aee aeg aeo ag- aga agb agc age agg ago aoa aob aoc aoe aog aoo baa bab bac bae bag bao bba bbb bbc bbe bbg bbo bca bcb bcc bce bcg bco be- bea beb bec bee beg beo bga bgb bgc bge bgg bgo boa bob boc boe bog boo c-- caa cab cac cae cag cao cba cbb cbc cbe cbg cbo cca ccb ccc cce ccg cco ce- cea ceb cec cee ceg ceo cga cgb cgc cge cgg cgo co- coa cob coc coe cog coo eaa eab eac eae eag eao eba ebb ebc ebe ebg ebo ec- eca ecb ecc ece ecg eco eea eeb eec eee eeg eeo ega egb egc ege egg ego eo- eoa eob eoc eoe eog eoo gaa gab gac gae gag gao gba gbc gbe gbg gbo gca gcb gcc gce gcg gco ge- gea geb gec gee geg geo gga ggb ggc ggg ggo goa gob goc goe gog goo oaa oab oac oae oag oao ob- oba obb obc obe obg obo oc- oca ocb occ ocg oco oea oeb oec oee oeg oeo oga ogc oge ogg ogo oo- ooa oob ooc oog ooo