a-a a-b aaa aab aae aag aak aao aas ab- aba abb abe abg abk abo abs aea aeb aee aeg aek aeo aes ag- aga agb age agg agk ago ags aka akb ake akg akk ako aks aoa aob aoe aog aok aoo aos as- asa asb ase asg ask aso ass baa bab bae bag bak bao bas bba bbb bbe bbg bbk bbo bbs be- bea beb bee beg bek beo bes bga bgb bge bgg bgk bgo bgs bka bkb bke bkg bkk bko bks boa bob boe bog bok boo bos bsa bsb bse bsg bsk bso bss eaa eab eae eag eak eao eas eba ebb ebe ebg ebk ebo ebs eea eeb eee eeg eek eeo ees ega egb ege egg ego egs eka ekb eke ekg eko eks eo- eoa eob eoe eog eok eoo eos es- esa esb ese esg esk eso ess gaa gab gae gag gak gao gas gba gbe gbg gbk gbo gbs ge- gea geb gee geg gek geo ges gga ggb ggg ggo ggs gka gkb gko gks goa gob goe gog gok goo gos gsa gsb gse gsg gsk gso gss ka- kaa kab kae kag kak kao kas kba kbb kbe kbk kbo kbs ke- kea keb kee keg kek keo kes kga kgb kgo kgs kkb kke kkk kks koa kob koe kog kok koo kos ksa ksb kse ksg ksk kso kss oaa oab oae oag oak oao oas ob- oba obb obe obg obk obo obs oea oeb oee oeg oeo oes oga oge ogg ogo ogs oka okb oke okg okk oko oks oo- ooa oob oog ook ooo oos os- osa osb ose osg osk oso oss saa sab sae sag sak sao sas sba sbb sbe sbg sbk sbo sbs se- sea seb see seg sek seo ses sga sgb sge sgg sgk sgo sgs sk- ska skb ske skg skk sko sks soa sob soe sog sok soo sos ss- ssa ssb sse ssg ssk sso sss