a-a a-b aaa aab aae aag aah aao ab- aba abb abe abg abh abo aea aeb aee aeg aeh aeo ag- aga agb age agg agh ago aha ahb ahe ahg ahh aho aoa aob aoe aog aoh aoo baa bab bae bag bah bao bba bbb bbe bbg bbh bbo be- bea beb bee beg beh beo bga bgb bge bgg bgh bgo bha bhb bhe bhg bhh bho boa bob boe bog boh boo eaa eab eae eag eah eao eba ebb ebe ebg ebh ebo eea eeb eee eeg eeo ega egb ege egg egh ego eha ehb ehe ehg ehh eho eo- eoa eob eoe eog eoh eoo gaa gab gae gag gah gao gba gbe gbg gbh gbo ge- gea geb gee geg geh geo gga ggb ggg ggh ggo gha ghb ghe ghg ghh gho goa gob goe gog goh goo haa hab hae hag hah hao hba hbb hbe hbg hbh hbo he- hea heb hee heg heh heo hga hgb hge hgg hgh hgo hha hhb hhe hhg hhh hho hoa hob hoe hog hoh hoo oaa oab oae oag oah oao ob- oba obb obe obg obh obo oea oeb oee oeg oeh oeo oga oge ogg ogh ogo oha ohe ohg ohh oho oo- ooa oob oog ooh ooo