a-a a-b a-i aaa aab aai aao aar aas aay ab- aba abb abi abo abr abs aby ai- aia aib aii aio air ais aiy aoa aob aoi aoo aor aos ar- ara arb ari aro arr ars ary as- asa asb asi aso asr ass asy ay- aya ayi ayo ayr ays baa bab bai bao bar bas bay bba bbb bbi bbo bbr bbs bby bi- bia bib bii bio bir bis biy boa bob boi boo bor bos boy bra brb bri bro brr brs bry bsa bsb bsi bso bsr bss bsy by- bya byi byo byr bys ia- iaa iab iai iao iar ias iba ibb ibi ibo ibr ibs iby iia iib iii iio iir iis io- ioa iob ioi ioo ior ios ir- ira irb iri iro irr irs iry is- isa isb isi iso isr iss isy iya iyo iyr iys iyy o-i oaa oab oai oao oar oas ob- oba obb obi obo obr obs oby oia oib oii oio oir ois oo- ooa oob ooi ooo oor oos or- ora orb ori oro orr ors ory os- osa osb osi oso osr oss oya oyi oyo oys ra- raa rab rai rao rar ras ray rba rbb rbi rbo rbr rbs ria rib rii rio rir ris riy roa rob roi roo ror ros roy rra rrb rri rrr rrs rsa rsb rsi rso rsr rss ry- rya ryo ryr rys ryy saa sab sai sao sar sas say sba sbb sbi sbo sbr sbs sby sia sib sii sio sir sis soa sob soi soo sor sos soy sr- sra srb sri sro srr srs sry ss- ssa ssb ssi sso ssr sss sy- sya syb syi syr sys yaa yab yai yao yar yas yay ybi ybr ybs yby yii yio yir yis yob yoi yoo yor yos yoy yra yro yrs ysa ysb ysi yso ysr yss ysy yyb yys yyy