a-a a-b aaa aab aad aak aao aay ab- aba abb abd abk abo aby ad- ada adb add adk ado ady aka akb akd akk ako aoa aob aod aok aoo ay- aya ayd ayk ayo baa bab bad bak bao bay bba bbb bbd bbk bbo bby bda bdb bdd bdk bdo bdy bka bkb bkk bko boa bob bod bok boo boy by- bya byd byk byo daa dab dad dak dao day dba dbb dbd dbk dbo dby dda ddb ddd ddk ddo ddy dka dkb dkk dko doa dob dod dok doo doy dy- dya dyb dyd dyk dyo dyy ka- kaa kab kad kak kao kay kba kbb kbd kbk kbo kda kdb kdk kdo kdy kkb kkk kky koa kob kod kok koo koy kya kyd kyo oaa oab oad oak oao ob- oba obb obd obk obo oby oda odb odd odo oka okb okd okk oko oo- ooa oob ood ook ooo oya oyd oyo yaa yab yad yak yao yay yby yda ydo ydy yka ykk yob yod yok yoo yoy yyb yyy