a-a a-b a-z aaa aab aak aao aar aau aaz ab- aba abb abk abo abr abu abz aka akb akk ako akr aku aoa aob aok aoo aor aou ar- ara arb ark aro arr aru arz au- aua aub auk auo aur auz az- aza azb azo azu azz b-u baa bab bak bao bar bau baz bba bbb bbk bbo bbr bbu bka bkb bkk bko bkr boa bob bok boo bor bou boz bra brb brk bro brr bru brz bua bub buk buo bur buu buz bza bzo bzr bzu bzz k-z ka- kaa kab kak kao kar kau kaz kba kbb kbk kbo kbr kbu kbz kkb kkk kkr kku koa kob kok koo kor kou koz kra krk kro krr kru kub kuk kur kuu kzo oaa oab oak oao oar oau ob- oba obb obk obo obr obu oka okb okk oko okr oku oo- ooa oob ook ooo oor or- ora orb ork oro orr oru orz ou- oua ouk ouo our oza ozo ozu ozz ra- raa rab rak rao rar rau raz rba rbb rbk rbo rbr rbu rkb rkk rko rku rkz roa rob rok roo ror rou roz rra rrb rrk rrr rru rua rub ruk ruo rur ruu ruz rza rzb rzo ua- uaa uab uak uao uar uau uaz uba ubb ubk ubo ubr ubu uka ukb ukk ukr uku ukz uoa uob uok uoo uor ur- ura urb urk uro urr uru urz uua uur uuu uza uzb uzo uzu zaa zab zak zao zar zaz zbb zbr zka zo- zoa zob zok zoo zor zou zro zub zuk zur zuz zzr zzz