-ol bbb bbd bbk bbl bbo bbs bdb bdd bdk bdl bdo bds bkb bkk bkl bko bks blb bld blk bll blo bls bob bod bok bol boo bos bsb bsd bsk bsl bso bss dbb dbd dbk dbl dbo dbs ddb ddd ddk ddl ddo dds dkb dkk dkl dko dks dl- dlb dld dlk dll dlo dls dob dod dok dol doo dos dsb dsd dsk dsl dso dss kbb kbd kbk kbl kbo kbs kdb kdk kdl kdo kds kkb kkk kkl kks kl- klb kld klo kls kob kod kok kol koo kos ksb ksd ksk ksl kso kss lbb lbd lbk lbl lbo lbs ldb ldd ldk ldl ldo lds lkb lkl lks llb lld llk lll llo lls lob lod lok lol loo los lsb lsd lsk lsl lso lss ob- obb obd obk obl obo obs odb odd odl odo ods okb okd okk okl oko oks olb old olk oll olo ols oo- oob ood ook ool ooo oos os- osb osd osk osl oso oss sbb sbd sbk sbl sbo sbs sdb sdd sdk sdl sdo sds sk- skb skd skk skl sko sks slb sld slk sll slo sls sob sod sok sol soo sos ss- ssb ssd ssk ssl sso sss