a-a a-b a-i a-t aaa aab aai aao aas aat aay ab- aba abb abi abo abs abt aby ai- aia aib aii aio ais ait aiy aoa aob aoi aoo aos aot as- asa asb asi aso ass ast asy at- ata atb ati ato ats att ay- aya ayi ayo ays ayt baa bab bai bao bas bat bay bba bbb bbi bbo bbs bbt bby bi- bia bib bii bio bis bit biy boa bob boi boo bos bot boy bsa bsb bsi bso bss bst bsy bta btb bti bto bts btt bty by- bya byi byo bys byt ia- iaa iab iai iao ias iat iba ibb ibi ibo ibs ibt iby iia iib iii iio iis iit io- ioa iob ioi ioo ios iot is- isa isb isi iso iss ist isy ita itb iti ito its itt ity iya iyo iys iyt iyy o-i oaa oab oai oao oas oat ob- oba obb obi obo obs obt oby oia oib oii oio ois oit oo- ooa oob ooi ooo oos oot os- osa osb osi oso oss ost ot- ota otb oti oto ots ott oya oyi oyo oys saa sab sai sao sas sat say sba sbb sbi sbo sbs sbt sby sia sib sii sio sis sit soa sob soi soo sos sot soy ss- ssa ssb ssi sso sss sst sta stb sti sto sts stt sty sy- sya syb syi sys syt taa tab tai tao tas tat tay tba tbb tbi tbo tbs tbt tia tib tii tio tis tit tiy to- toa tob toi too tos tot toy tsa tsb tsi tso tss tst tsy tta ttb tti tto tts ttt tty tya tyo tys tyt yaa yab yai yao yas yat yay ybi ybs yby yii yio yis yit yob yoi yoo yos yot yoy ysa ysb ysi yso yss yst ysy yta yto yts ytt yyb yys yyt yyy