bbb bbc bbo bbs bbt bby bcb bcc bco bcs bct bcy bob boc boo bos bot boy bsb bsc bso bss bst bsy btb btc bto bts btt bty by- byc byo bys byt c-- cbb cbc cbo cbs cbt cby ccb ccc cco ccs cct co- cob coc coo cos cot coy csb csc cso css cst csy ctb ctc cto cts ctt cty cyb cyc cyo cys cyt ob- obb obc obo obs obt oby oc- ocb occ oco ocs oct oo- oob ooc ooo oos oot os- osb osc oso oss ost ot- otb otc oto ots ott oyo oys sbb sbc sbo sbs sbt sby scb scc sco scs sct sob soc soo sos sot soy ss- ssb ssc sso sss sst stb stc sto sts stt sty sy- syb syc sys syt tbb tbc tbo tbs tbt tcb tcc tco tcs tct to- tob toc too tos tot toy tsb tsc tso tss tst tsy ttb ttc tto tts ttt tty tyc tyo tys tyt ybc ybs yby ycc yco ycs ycy yob yoc yoo yos yot yoy ysb ysc yso yss yst ysy ytc yto yts ytt yyb yyc yys yyt yyy