bbbb bbbs bcbc bcbs bccc bccs bcos bcsc bcss bctc bcts bobb bobo bobs boco bocs boob booc boos boot bosc boso boss bost botb boto bots bott bscs bsos bssc bsts btcc btcs btob btss bttb c-bo cbbc cbbs cbcc cbcs cbct cbot cbsc cbtc ccbc cccb cccc cccs ccob ccoc ccss ccst cctb cctc cctt cobb cobo cobs coco coct coob coos coot cosc coso coss cost cotb cotc coto cots cott cscb cscc csco cscs csob csos csot cstc csto csts ctbs ctos ctot ctsc ctss ctts obbo obos obot obss obst obts ocbc occc occt ocos oct- octo octs oooo ooos oost ootb oots oscc osco osoo osos ossb osso ostc osts otbs oto- otoo otos otso otto otts s-os sbbs sbcc sbcs sbct sbot sbst sbtc sccc sccs scct scob scoo scot scsc scso scst sctc scto scts sobo sobs sobt soco socs soos soot soso soss sost sotc soto sots sscc sscs ssoc ssot sssb sssc ssss sstb sstc ssts stbc stbs stcc stcs stob stoo stos stot stss sttc tbbs tbcb tbcc tbst tcbs tccc tcos tctc tcts tobo tobs tobt toco toos toot tosb tosc toso toss tost totc toto tots tott tsbc tscc tsob tsos tsst tstc tsts ttbb ttss tttt