a-a a-b aaa aab aae aag aao aas ab- aba abb abe abg abo abs aea aeb aee aeg aeo aes ag- aga agb age agg ago ags aoa aob aoe aog aoo aos as- asa asb ase asg aso ass baa bab bae bag bao bas bba bbb bbe bbg bbo bbs be- bea beb bee beg beo bes bga bgb bge bgg bgo bgs boa bob boe bog boo bos bsa bsb bse bsg bso bss eaa eab eae eag eao eas eba ebb ebe ebg ebo ebs eea eeb eee eeg eeo ees ega egb ege egg ego egs eo- eoa eob eoe eog eoo eos es- esa esb ese esg eso ess gaa gab gae gag gao gas gba gbe gbg gbo gbs ge- gea geb gee geg geo ges gga ggb ggg ggo ggs goa gob goe gog goo gos gsa gsb gse gsg gso gss oaa oab oae oag oao oas ob- oba obb obe obg obo obs oea oeb oee oeg oeo oes oga oge ogg ogo ogs oo- ooa oob oog ooo oos os- osa osb ose osg oso oss saa sab sae sag sao sas sba sbb sbe sbg sbo sbs se- sea seb see seg seo ses sga sgb sge sgg sgo sgs soa sob soe sog soo sos ss- ssa ssb sse ssg sso sss