a-a a-b a-i aaa aab aai aao aar aay ab- aba abb abi abo abr aby ai- aia aib aii aio air aiy aoa aob aoi aoo aor ar- ara arb ari aro arr ary ay- aya ayi ayo ayr baa bab bai bao bar bay bba bbb bbi bbo bbr bby bi- bia bib bii bio bir biy boa bob boi boo bor boy bra brb bri bro brr bry by- bya byi byo byr ia- iaa iab iai iao iar iba ibb ibi ibo ibr iby iia iib iii iio iir io- ioa iob ioi ioo ior ir- ira irb iri iro irr iry iya iyo iyr iyy o-i oaa oab oai oao oar ob- oba obb obi obo obr oby oia oib oii oio oir oo- ooa oob ooi ooo oor or- ora orb ori oro orr ory oya oyi oyo ra- raa rab rai rao rar ray rba rbb rbi rbo rbr ria rib rii rio rir riy roa rob roi roo ror roy rra rrb rri rrr ry- rya ryo ryr ryy yaa yab yai yao yar yay ybi ybr yby yii yio yir yob yoi yoo yor yoy yra yro yyb yyy