a-a a-b aaa aab aag aao aas aay ab- aba abb abg abo abs aby ag- aga agb agg ago ags agy aoa aob aog aoo aos as- asa asb asg aso ass asy ay- aya ayo ays baa bab bag bao bas bay bba bbb bbg bbo bbs bby bga bgb bgg bgo bgs boa bob bog boo bos boy bsa bsb bsg bso bss bsy by- bya byg byo bys gaa gab gag gao gas gay gba gbg gbo gbs gby gga ggb ggg ggo ggs goa gob gog goo gos goy gsa gsb gsg gso gss gy- gya gyb gyo gys oaa oab oag oao oas ob- oba obb obg obo obs oby oga ogg ogo ogs ogy oo- ooa oob oog ooo oos os- osa osb osg oso oss oya oyo oys saa sab sag sao sas say sba sbb sbg sbo sbs sby sga sgb sgg sgo sgs soa sob sog soo sos soy ss- ssa ssb ssg sso sss sy- sya syb syg sys yaa yab yag yao yas yay ybg ybs yby yga ygo yob yog yoo yos yoy ysa ysb ysg yso yss ysy yyb yyg yys yyy