bbb bbm bbo bbs bbt bmb bmm bmo bms bmt bob bom boo bos bot bsb bsm bso bss bst btb btm bto bts btt m-o mbb mbm mbo mbs mbt mmb mmm mmo mms mmt mob mom moo mos mot msb msm mso mss mst mtb mtm mto mts mtt ob- obb obm obo obs obt om- omb omm omo oms omt oo- oob oom ooo oos oot os- osb osm oso oss ost ot- otb otm oto ots ott sbb sbm sbo sbs sbt smb smm smo sms smt sob som soo sos sot ss- ssb ssm sso sss sst stb stm sto sts stt tbb tbm tbo tbs tbt tmb tmm tmo tms tmt to- tob tom too tos tot tsb tsm tso tss tst ttb ttm tto tts ttt