a-a a-b aaa aab aak aao aar aau aay ab- aba abb abk abo abr abu aby aka akb akk ako akr aku aoa aob aok aoo aor aou ar- ara arb ark aro arr aru ary au- aua aub auk auo aur ay- aya ayk ayo ayr ayu b-u baa bab bak bao bar bau bay bba bbb bbk bbo bbr bbu bby bka bkb bkk bko bkr boa bob bok boo bor bou boy bra brb brk bro brr bru bry bua bub buk buo bur buu buy by- bya byk byo byr byu ka- kaa kab kak kao kar kau kay kba kbb kbk kbo kbr kbu kkb kkk kkr kku kky koa kob kok koo kor kou koy kra krk kro krr kru kry kub kuk kur kuu kuy kya kyo kyr kyu oaa oab oak oao oar oau ob- oba obb obk obo obr obu oby oka okb okk oko okr oku oo- ooa oob ook ooo oor or- ora orb ork oro orr oru ory ou- oua ouk ouo our oya oyo ra- raa rab rak rao rar rau ray rba rbb rbk rbo rbr rbu rkb rkk rko rku rky roa rob rok roo ror rou roy rra rrb rrk rrr rru rua rub ruk ruo rur ruu ruy ry- rya ryk ryo ryr ryu ryy ua- uaa uab uak uao uar uau uay uba ubb ubk ubo ubr ubu uby uka ukb ukk ukr uku uoa uob uok uoo uor ur- ura urb urk uro urr uru ury uua uur uuu uyo uyu yaa yab yak yao yar yau yay ybr yby yka ykk yob yok yoo yor you yoy yra yro yru yua yuk yuo yur yuu yuy yyb yyu yyy