a-a a-b a-i aaa aab aai aav aay ab- aba abb abi abv aby ai- aia aib aii aiv aiy av- ava avb avi avy ay- aya ayi baa bab bai bav bay bba bbb bbi bby bi- bia bib bii biv biy bva bvb bvi bvv by- bya byi i-v ia- iaa iab iai iav iba ibb ibi ibv iby iia iib iii iva ivb ivi ivv ivy iya iyy v-a vaa vab vai vav vay vba vbi vbv vi- via vib vii viv viy vva vvb vvi vvv yaa yab yai yav yay ybi yby yii yva yvi yvy yyb yyy