a-a a-b aaa aab aak aao aar aaw ab- aba abb abk abo abr abw aka akb akk ako akr akw aoa aob aok aoo aor aow ar- ara arb ark aro arr arw aw- awa awb awk awo awr aww baa bab bak bao bar baw bba bbb bbk bbo bbr bbw bka bkb bkk bko bkr bkw boa bob bok boo bor bow bra brb brk bro brr brw bwa bwb bwk bwo bwr ka- kaa kab kak kao kar kaw kba kbb kbk kbo kbr kbw kkb kkk kkr koa kob kok koo kor kow kra krk kro krr krw kw- kwa kwk kwo kww oaa oab oak oao oar oaw ob- oba obb obk obo obr obw oka okb okk oko okr okw oo- ooa oob ook ooo oor oow or- ora orb ork oro orr owa owb owk owo oww ra- raa rab rak rao rar raw rba rbb rbk rbo rbr rbw rkb rkk rko roa rob rok roo ror row rra rrb rrk rrr rwa rwb rwr waa wab wak wao war waw wba wbb wbo wbr wbw wka wkb wko wkr wkw woa wob wok woo wor wow wr- wra wrk wro wrr wrw wwa wwo www