a-a a-b a-i aaa aab aag aai aak aao aar aav ab- aba abb abg abi abk abo abr abv ag- aga agb agg agi agk ago agr agv ai- aia aib aig aii aik aio air aiv aka akb akg aki akk ako akr akv aoa aob aog aoi aok aoo aor aov ar- ara arb arg ari ark aro arr arv av- ava avb avg avi avk avo avr baa bab bag bai bak bao bar bav bba bbb bbg bbi bbk bbo bbr bga bgb bgg bgi bgk bgo bgr bgv bi- bia bib big bii bik bio bir biv bka bkb bkg bkk bko bkr bkv boa bob bog boi bok boo bor bov bra brb brg bri brk bro brr brv bva bvb bvg bvi bvk bvo bvr bvv gaa gab gag gai gak gao gar gav gba gbg gbi gbk gbo gbr gbv gga ggb ggg ggi ggo ggr ggv gia gib gig gii gik gio gir giv gka gkb gko goa gob gog goi gok goo gor gov gra grb grg gri grk gro grr grv gva gvb gvg gvi gvk gvo gvr i-v ia- iaa iab iag iai iao iar iav iba ibb ibg ibi ibk ibo ibr ibv iga igb igg igi igk igo igr iia iib iii iio iir ika ikb iki ikk iko ikr ikv io- ioa iob iog ioi ioo ior iov ir- ira irb irg iri irk iro irr irv iva ivb ivg ivi ivo ivr ivv ka- kaa kab kag kai kak kao kar kav kba kbb kbi kbk kbo kbr kga kgb kgi kgo kgv kia kib kig kii kik kio kir kiv kkb kki kkk kkr kkv koa kob kog koi kok koo kor kra krg kri krk kro krr krv kva kvb kvi kvk kvo kvr kvv o-i oaa oab oag oai oak oao oar oav ob- oba obb obg obi obk obo obr obv oga ogg ogi ogo oia oib oii oik oio oir oiv oka okb okg oki okk oko okr oo- ooa oob oog ooi ook ooo oor oov or- ora orb org ori ork oro orr orv ov- ova ovb ovi ovo ovv ra- raa rab rag rai rak rao rar rav rba rbb rbg rbi rbk rbo rbr rga rgb rgg rgi rgk rgo rgr rgv ria rib rig rii rik rio rir riv rkb rkg rkk rko rkv roa rob rog roi rok roo ror rov rra rrb rrg rri rrk rrr rva rvb rvg rvi rvo rvr rvv v-a vaa vab vag vai vak vao var vav vba vbg vbi vbk vbo vbr vbv vga vgg vgo vgr vi- via vib vig vii vik vio vir viv vka vkb vkg voa vob vog voi vok voo vor vov vra vrb vrg vri vrk vrr vva vvb vvg vvi vvo vvr vvv