a-a a-b a-i aaa aab aai aak aao aar aav ab- aba abb abi abk abo abr abv ai- aia aib aii aik aio air aiv aka akb aki akk ako akr akv aoa aob aoi aok aoo aor aov ar- ara arb ari ark aro arr arv av- ava avb avi avk avo avr baa bab bai bak bao bar bav bba bbb bbi bbk bbo bbr bi- bia bib bii bik bio bir biv bka bkb bkk bko bkr bkv boa bob boi bok boo bor bov bra brb bri brk bro brr brv bva bvb bvi bvk bvo bvr bvv i-v ia- iaa iab iai iao iar iav iba ibb ibi ibk ibo ibr ibv iia iib iii iio iir ika ikb iki ikk iko ikr ikv io- ioa iob ioi ioo ior iov ir- ira irb iri irk iro irr irv iva ivb ivi ivo ivr ivv ka- kaa kab kai kak kao kar kav kba kbb kbi kbk kbo kbr kia kib kii kik kio kir kiv kkb kki kkk kkr kkv koa kob koi kok koo kor kra kri krk kro krr krv kva kvb kvi kvk kvo kvr kvv o-i oaa oab oai oak oao oar oav ob- oba obb obi obk obo obr obv oia oib oii oik oio oir oiv oka okb oki okk oko okr oo- ooa oob ooi ook ooo oor oov or- ora orb ori ork oro orr orv ov- ova ovb ovi ovo ovv ra- raa rab rai rak rao rar rav rba rbb rbi rbk rbo rbr ria rib rii rik rio rir riv rkb rkk rko rkv roa rob roi rok roo ror rov rra rrb rri rrk rrr rva rvb rvi rvo rvr rvv v-a vaa vab vai vak vao var vav vba vbi vbk vbo vbr vbv vi- via vib vii vik vio vir viv vka vkb voa vob voi vok voo vor vov vra vrb vri vrk vrr vva vvb vvi vvo vvr vvv