bbb bbf bbm bbo bbs bfb bff bfm bfo bfs bmb bmf bmm bmo bms bob bof bom boo bos bsb bsf bsm bso bss fbb fbf fbm fbo fbs fff ffm ffo ffs fmb fmf fmm fmo fms fob fof fom foo fos fsb fsf fsm fso fss m-f m-o mbb mbf mbm mbo mbs mfb mff mfm mfo mfs mmb mmf mmm mmo mms mob mof mom moo mos msb msf msm mso mss ob- obb obf obm obo obs of- ofb off ofm ofo ofs om- omb omf omm omo oms oo- oob oof oom ooo oos os- osb osf osm oso oss sbb sbf sbm sbo sbs sfb sff sfm sfo sfs smb smf smm smo sms sob sof som soo sos ss- ssb ssf ssm sso sss