a-a a-b aaa aab aak aao aas aaw ab- aba abb abk abo abs abw aka akb akk ako aks akw aoa aob aok aoo aos aow as- asa asb ask aso ass asw aw- awa awb awk awo aws aww baa bab bak bao bas baw bba bbb bbk bbo bbs bbw bka bkb bkk bko bks bkw boa bob bok boo bos bow bsa bsb bsk bso bss bsw bwa bwb bwk bwo bws ka- kaa kab kak kao kas kaw kba kbb kbk kbo kbs kbw kkb kkk kks koa kob kok koo kos kow ksa ksb ksk kso kss ksw kw- kwa kwk kwo kws kww oaa oab oak oao oas oaw ob- oba obb obk obo obs obw oka okb okk oko oks okw oo- ooa oob ook ooo oos oow os- osa osb osk oso oss osw owa owb owk owo ows oww saa sab sak sao sas saw sba sbb sbk sbo sbs sbw sk- ska skb skk sko sks skw soa sob sok soo sos sow ss- ssa ssb ssk sso sss ssw swa swb swk swo sws waa wab wak wao was waw wba wbb wbo wbs wbw wka wkb wko wks wkw woa wob wok woo wos wow wsa wsb wsk wso wss wsw wwa wwo www