a-a a-b a-t aaa aab aao aar aas aat aay ab- aba abb abo abr abs abt aby aoa aob aoo aor aos aot ar- ara arb aro arr ars art ary as- asa asb aso asr ass ast asy at- ata atb ato atr ats att ay- aya ayo ayr ays ayt baa bab bao bar bas bat bay bba bbb bbo bbr bbs bbt bby boa bob boo bor bos bot boy bra brb bro brr brs brt bry bsa bsb bso bsr bss bst bsy bta btb bto btr bts btt bty by- bya byo byr bys byt oaa oab oao oar oas oat ob- oba obb obo obr obs obt oby oo- ooa oob ooo oor oos oot or- ora orb oro orr ors ort ory os- osa osb oso osr oss ost ot- ota otb oto otr ots ott oya oyo oys ra- raa rab rao rar ras rat ray rba rbb rbo rbr rbs rbt roa rob roo ror ros rot roy rra rrb rrr rrs rrt rsa rsb rso rsr rss rst rta rtb rto rtr rts rtt rty ry- rya ryo ryr rys ryy saa sab sao sar sas sat say sba sbb sbo sbr sbs sbt sby soa sob soo sor sos sot soy sr- sra srb sro srr srs srt sry ss- ssa ssb sso ssr sss sst sta stb sto str sts stt sty sy- sya syb syr sys syt taa tab tao tar tas tat tay tba tbb tbo tbr tbs tbt to- toa tob too tor tos tot toy tra trb tro trr trs trt try tsa tsb tso tsr tss tst tsy tta ttb tto ttr tts ttt tty tya tyo tyr tys tyt yaa yab yao yar yas yat yay ybr ybs yby yob yoo yor yos yot yoy yra yro yrs yrt ysa ysb yso ysr yss yst ysy yta yto ytr yts ytt yyb yys yyt yyy