bbb bbc bbk bbo bbs bbt bby bcb bcc bck bco bcs bct bcy bkb bkc bkk bko bks bkt bob boc bok boo bos bot boy bsb bsc bsk bso bss bst bsy btb btc btk bto bts btt bty by- byc byk byo bys byt c-- cbb cbc cbk cbo cbs cbt cby ccb ccc cck cco ccs cct ckb ckc cko cks ckt cky co- cob coc cok coo cos cot coy csb csc csk cso css cst csy ctb ctc ctk cto cts ctt cty cyb cyc cyk cyo cys cyt k-t kbb kbc kbk kbo kbs kcb kcc kck kcs kct kkb kkc kkk kks kkt kky kob koc kok koo kos kot koy ksb ksc ksk kso kss kst ktb ktc ktk kto kts ktt kyc kyo kys kyt ob- obb obc obk obo obs obt oby oc- ocb occ ock oco ocs oct okb okc okk oko oks oo- oob ooc ook ooo oos oot os- osb osc osk oso oss ost ot- otb otc otk oto ots ott oyo oys sbb sbc sbk sbo sbs sbt sby scb scc sck sco scs sct sk- skb skc skk sko sks skt sky sob soc sok soo sos sot soy ss- ssb ssc ssk sso sss sst stb stc stk sto sts stt sty sy- syb syc syk sys syt tbb tbc tbk tbo tbs tbt tcb tcc tck tco tcs tct tkb tkc tkk tko tks tkt tky to- tob toc tok too tos tot toy tsb tsc tsk tso tss tst tsy ttb ttc ttk tto tts ttt tty tyc tyo tys tyt ybc ybs yby ycc yco ycs ycy ykk yob yoc yok yoo yos yot yoy ysb ysc ysk yso yss yst ysy ytc ytk yto yts ytt yyb yyc yys yyt yyy