a-a a-b a-i aaa aab aai aak aao aav ab- aba abb abi abk abo abv ai- aia aib aii aik aio aiv aka akb aki akk ako akv aoa aob aoi aok aoo aov av- ava avb avi avk avo baa bab bai bak bao bav bba bbb bbi bbk bbo bi- bia bib bii bik bio biv bka bkb bkk bko bkv boa bob boi bok boo bov bva bvb bvi bvk bvo bvv i-v ia- iaa iab iai iao iav iba ibb ibi ibk ibo ibv iia iib iii iio ika ikb iki ikk iko ikv io- ioa iob ioi ioo iov iva ivb ivi ivo ivv ka- kaa kab kai kak kao kav kba kbb kbi kbk kbo kia kib kii kik kio kiv kkb kki kkk kkv koa kob koi kok koo kva kvb kvi kvk kvo kvv o-i oaa oab oai oak oao oav ob- oba obb obi obk obo obv oia oib oii oik oio oiv oka okb oki okk oko oo- ooa oob ooi ook ooo oov ov- ova ovb ovi ovo ovv v-a vaa vab vai vak vao vav vba vbi vbk vbo vbv vi- via vib vii vik vio viv vka vkb voa vob voi vok voo vov vva vvb vvi vvo vvv