bbb bbc bbo bbr bbs bbt bby bcb bcc bco bcr bcs bct bcy bob boc boo bor bos bot boy brb bro brr brs brt bry bsb bsc bso bsr bss bst bsy btb btc bto btr bts btt bty by- byc byo byr bys byt c-- cbb cbc cbo cbr cbs cbt cby ccb ccc cco ccr ccs cct co- cob coc coo cor cos cot coy crb crc cro crr crs crt cry csb csc cso csr css cst csy ctb ctc cto ctr cts ctt cty cyb cyc cyo cyr cys cyt ob- obb obc obo obr obs obt oby oc- ocb occ oco ocr ocs oct oo- oob ooc ooo oor oos oot or- orb orc oro orr ors ort ory os- osb osc oso osr oss ost ot- otb otc oto otr ots ott oyo oys rbb rbc rbo rbr rbs rbt rcb rcc rco rcr rcs rct rob roc roo ror ros rot roy rrb rrc rrr rrs rrt rsb rsc rso rsr rss rst rtb rtc rto rtr rts rtt rty ry- ryc ryo ryr rys ryy sbb sbc sbo sbr sbs sbt sby scb scc sco scr scs sct sob soc soo sor sos sot soy sr- srb src sro srr srs srt sry ss- ssb ssc sso ssr sss sst stb stc sto str sts stt sty sy- syb syc syr sys syt tbb tbc tbo tbr tbs tbt tcb tcc tco tcr tcs tct to- tob toc too tor tos tot toy trb trc tro trr trs trt try tsb tsc tso tsr tss tst tsy ttb ttc tto ttr tts ttt tty tyc tyo tyr tys tyt ybc ybr ybs yby ycc yco ycs ycy yob yoc yoo yor yos yot yoy yrc yro yrs yrt ysb ysc yso ysr yss yst ysy ytc yto ytr yts ytt yyb yyc yys yyt yyy