bbb bbc bbm bbo bbs bcb bcc bcm bco bcs bmb bmc bmm bmo bms bob boc bom boo bos bsb bsc bsm bso bss c-- cbb cbc cbm cbo cbs ccb ccc ccm cco ccs cmb cmc cmm cmo cms co- cob coc com coo cos csb csc csm cso css m-o mbb mbc mbm mbo mbs mc- mcb mcc mcm mco mcs mmb mmc mmm mmo mms mob moc mom moo mos msb msc msm mso mss ob- obb obc obm obo obs oc- ocb occ ocm oco ocs om- omb omc omm omo oms oo- oob ooc oom ooo oos os- osb osc osm oso oss sbb sbc sbm sbo sbs scb scc scm sco scs smb smc smm smo sms sob soc som soo sos ss- ssb ssc ssm sso sss