bbbb bbbs bbrc bcbc bcbs bccc bccs bcor bcos bcrs bcsc bcss bctc bcts bobb bobo bobs boco bocs boob booc boor boos boot bor- boro borr bors bort bosc boso boss bost botb boto bots bott brcb brob broc broo bror bros brot brrr brrs brsb brsr brst brtc bscs bsos bssc bsts btcc btcs btob btor btrc btrt btss bttb c-bo cbbc cbbs cbcc cbcr cbcs cbct cbot cbrt cbsc cbtc ccbc cccb cccc cccs ccob ccoc ccrc ccrs ccrt ccss ccst cctb cctc cctt cobb cobo cobs coco coct coob coos coot cor- corb corc coro corr cors cort cosc coso coss cost cotb cotc coto cots cott crbc crcc crcr crob croc croo cror crot crrt crss crst crtc crts cscb cscc csco cscr cscs csob csor csos csot csrc csrs cssr cstc csto cstr csts ctbs ctor ctos ctot ctrc ctrs ctsc ctss ctts obbo obor obos obot obro obsr obss obst obts ocbc occc occt ocos ocro ocrr ocrs oct- octo octs oocr oooo ooos oort oost ootb oots orbb orbo orbs orco orcs oro- oror oros orot orro orrs orso ortc orto orts oscc osco osoo osor osos osro ossb osso ostc ostr osts otbs oto- otoo otor otos otro otrs otso otto otts rbbb rbbr rbbs rbss rbst rcbc rcbo rccb rccc rccs rcos rcsc rcss rctc rcts rob- robb robo robs robt rocc roco rocs roob roor roos root rorc roro rort rosc roso ross rost rotc roto rotr rots rott rrrr rscc rscs rsos rsts rtcc rtss rtts s-os sbbs sbcc sbcs sbct sbor sbot sbst sbtc sccc sccs scct scob scoo scor scot scr- scrc scrs scsc scso scsr scst sctc scto sctr scts sobo sobr sobs sobt soco socr socs soor soos soot sorb soro sorr sors sort soso soss sost sotc soto sots srbc srcc srct sros srtr ssbr sscc sscs ssoc ssot ssrc ssrs sssb sssc ssss sstb sstc ssts stbc stbs stcc stcs stob stoo stor stos stot strc stro strs stss sttc sttr tbbs tbcb tbcc tbrb tbst tcbs tccc tcos tctc tcts tobo tobs tobt toco toor toos toot torc toro torr tors tort tosb tosc toso toss tost totc toto totr tots tott trcc troc troo tros trot trst trtc trtr tsbc tscc tsob tsos tssr tsst tstc tsts ttbb ttss tttt