a-a a-b aaa aab aag aao aar aav ab- aba abb abg abo abr abv ag- aga agb agg ago agr agv aoa aob aog aoo aor aov ar- ara arb arg aro arr arv av- ava avb avg avo avr baa bab bag bao bar bav bba bbb bbg bbo bbr bga bgb bgg bgo bgr bgv boa bob bog boo bor bov bra brb brg bro brr brv bva bvb bvg bvo bvr bvv gaa gab gag gao gar gav gba gbg gbo gbr gbv gga ggb ggg ggo ggr ggv goa gob gog goo gor gov gra grb grg gro grr grv gva gvb gvg gvo gvr oaa oab oag oao oar oav ob- oba obb obg obo obr obv oga ogg ogo oo- ooa oob oog ooo oor oov or- ora orb org oro orr orv ov- ova ovb ovo ovv ra- raa rab rag rao rar rav rba rbb rbg rbo rbr rga rgb rgg rgo rgr rgv roa rob rog roo ror rov rra rrb rrg rrr rva rvb rvg rvo rvr rvv v-a vaa vab vag vao var vav vba vbg vbo vbr vbv vga vgg vgo vgr voa vob vog voo vor vov vra vrb vrg vrr vva vvb vvg vvo vvr vvv