a-a a-b a-i aaa aab aai aao aas aay ab- aba abb abi abo abs aby ai- aia aib aii aio ais aiy aoa aob aoi aoo aos as- asa asb asi aso ass asy ay- aya ayi ayo ays baa bab bai bao bas bay bba bbb bbi bbo bbs bby bi- bia bib bii bio bis biy boa bob boi boo bos boy bsa bsb bsi bso bss bsy by- bya byi byo bys ia- iaa iab iai iao ias iba ibb ibi ibo ibs iby iia iib iii iio iis io- ioa iob ioi ioo ios is- isa isb isi iso iss isy iya iyo iys iyy o-i oaa oab oai oao oas ob- oba obb obi obo obs oby oia oib oii oio ois oo- ooa oob ooi ooo oos os- osa osb osi oso oss oya oyi oyo oys saa sab sai sao sas say sba sbb sbi sbo sbs sby sia sib sii sio sis soa sob soi soo sos soy ss- ssa ssb ssi sso sss sy- sya syb syi sys yaa yab yai yao yas yay ybi ybs yby yii yio yis yob yoi yoo yos yoy ysa ysb ysi yso yss ysy yyb yys yyy