a-a a-b a-c a-t aaa aab aac aao aar aas aat aay ab- aba abb abc abo abr abs abt aby ac- aca acb acc aco acr acs act acy aoa aob aoc aoo aor aos aot ar- ara arb arc aro arr ars art ary as- asa asb asc aso asr ass ast asy at- ata atb atc ato atr ats att ay- aya ayc ayo ayr ays ayt baa bab bac bao bar bas bat bay bba bbb bbc bbo bbr bbs bbt bby bca bcb bcc bco bcr bcs bct bcy boa bob boc boo bor bos bot boy bra brb bro brr brs brt bry bsa bsb bsc bso bsr bss bst bsy bta btb btc bto btr bts btt bty by- bya byc byo byr bys byt c-- caa cab cac cao car cas cat cay cba cbb cbc cbo cbr cbs cbt cby cca ccb ccc cco ccr ccs cct co- coa cob coc coo cor cos cot coy cra crb crc cro crr crs crt cry csa csb csc cso csr css cst csy cta ctb ctc cto ctr cts ctt cty cya cyb cyc cyo cyr cys cyt oaa oab oac oao oar oas oat ob- oba obb obc obo obr obs obt oby oc- oca ocb occ oco ocr ocs oct oo- ooa oob ooc ooo oor oos oot or- ora orb orc oro orr ors ort ory os- osa osb osc oso osr oss ost ot- ota otb otc oto otr ots ott oya oyo oys ra- raa rab rac rao rar ras rat ray rba rbb rbc rbo rbr rbs rbt rca rcb rcc rco rcr rcs rct roa rob roc roo ror ros rot roy rra rrb rrc rrr rrs rrt rsa rsb rsc rso rsr rss rst rta rtb rtc rto rtr rts rtt rty ry- rya ryc ryo ryr rys ryy saa sab sac sao sar sas sat say sba sbb sbc sbo sbr sbs sbt sby sca scb scc sco scr scs sct soa sob soc soo sor sos sot soy sr- sra srb src sro srr srs srt sry ss- ssa ssb ssc sso ssr sss sst sta stb stc sto str sts stt sty sy- sya syb syc syr sys syt taa tab tac tao tar tas tat tay tba tbb tbc tbo tbr tbs tbt tca tcb tcc tco tcr tcs tct to- toa tob toc too tor tos tot toy tra trb trc tro trr trs trt try tsa tsb tsc tso tsr tss tst tsy tta ttb ttc tto ttr tts ttt tty tya tyc tyo tyr tys tyt yaa yab yac yao yar yas yat yay ybc ybr ybs yby yca ycc yco ycs ycy yob yoc yoo yor yos yot yoy yra yrc yro yrs yrt ysa ysb ysc yso ysr yss yst ysy yta ytc yto ytr yts ytt yyb yyc yys yyt yyy