b-u bbb bbl bbn bbs bbt bbu blb bll bln bls blt blu bnb bnl bnn bns bnt bnu bsb bsl bsn bss bst bsu btb btl btn bts btt btu bub bul bun bus but buu lbb lbl lbs lbt lbu llb lll lln lls llt llu lnb lnl lnn lns lnt lnu lsb lsl lsn lss lst lsu ltb ltl lts ltt ltu lub lul lun lus lut luu nbb nbl nbn nbs nbt nbu nlb nll nln nls nlt nlu nnb nnl nnn nns nnt nnu nsb nsl nsn nss nst nsu ntb ntn nts ntt ntu nub nul nun nus nut nuu sbb sbl sbn sbs sbt sbu slb sll sln sls slt slu snb snl snn sns snt snu ss- ssb ssl ssn sss sst ssu stb stl stn sts stt stu sub sul sun sus sut suu tbb tbl tbn tbs tbt tbu tll tln tls tlt tlu tnb tnl tnn tns tnt tsb tsl tsn tss tst tsu ttb ttl ttn tts ttt ttu tub tul tun tus tut tuu ubb ubl ubn ubs ubt ubu ulb ull uln uls ult ulu un- unb unl unn uns unt unu usb usl usn uss ust usu utb utl utn uts utt utu uun uus uut uuu