a-a a-b a-z aaa aab aao aar aav aaz ab- aba abb abo abr abv abz aoa aob aoo aor aov ar- ara arb aro arr arv arz av- ava avb avo avr avz az- aza azb azo azz baa bab bao bar bav baz bba bbb bbo bbr boa bob boo bor bov boz bra brb bro brr brv brz bva bvb bvo bvr bvv bza bzo bzr bzz oaa oab oao oar oav ob- oba obb obo obr obv oo- ooa oob ooo oor oov or- ora orb oro orr orv orz ov- ova ovb ovo ovv oza ozo ozz ra- raa rab rao rar rav raz rba rbb rbo rbr roa rob roo ror rov roz rra rrb rrr rva rvb rvo rvr rvv rza rzb rzo v-a vaa vab vao var vav vaz vba vbo vbr vbv vbz voa vob voo vor vov voz vra vrb vrr vva vvb vvo vvr vvv vvz zaa zab zao zar zav zaz zbb zbr zbv zo- zoa zob zoo zor zro zzr zzz