bbbb bbbs bbdd bd-r bdii bdsd bibb bibi bibs bidi bidr bids biis birb bird biri birr birs birt bis- bisd biss bist bitd bits bitt brds brdt brid bris brit brrr brrs brsb brsr brst bsbd bsrd bssd bsts btdt btrt btss bttb dbit dbrs dbss dbtt dddd ddss ddts dibb dibs didi dids diii diis dird dirr dirs dirt dis- disd disi diss dist diti dits ditt drib drit drrs dsdr dsri dsrr dssi dsst dsts dtss ibid ibis ibrd ibri ibss ibtb ibts idid idir idis idss idts iiii iiis iiit iirs iisd iisi iisr iist iitr iitt irds iri- irid iris irri irrs irti irts isbd isbt isdb isds isis isit isri issi issr isss istd isti istr ists itbs itis itri itrs itsi rbbb rbbr rbbs rbds rbis rbsd rbss rbst rib- ribs ridd ridi rids riis riri rirs risd risi riss rist riti rits ritt rrrr rsbi rsdd rsds rsid rsis rsts rtdt rtss rtts s-ib s-ii sbbs sbds sbsd sbsi sbst sdds sdib sdrs sdss sibi sibs sidd sidi sidr sids siit siri sirr sirs sirt sisd sisi siss sist sit- sitd siti sits sitt srib sris srsd srtr ssbr ssdd ssid ssis ssit ssri ssrs sssb sssi ssss sstb sstd ssts stbd stbs stds stib stid stir stis stit strd stri strs stsi stss sttd sttr tbbs tbit tbrb tbst tddb tdis tdri tdss tibi tibs tidd tids tiit tirb tird tiri tirr tirs tisb tisi tiss tist titi tits titt tri- trib tris trit trsd trsi trst trtr tsbd tsdb tsid tsis tssi tssr tsst tsts ttbb ttss tttt