b-u bbb bbe bbn bbs bbt bbu bbx be- beb bee ben bes bet beu bex bnb bne bnn bns bnt bnu bnx bsb bse bsn bss bst bsu bsx btb bte btn bts btt btu btx bub bue bun bus but buu bux bxb bxn bxx ebb ebe ebn ebs ebt ebu ebx eeb eee een ees eet eex en- enb ene enn ens ent enu es- esb ese esn ess est esu esx etb ete etn ets ett etu etx eu- eub eue eun eus eut eux ex- exe exs ext exu exx nbb nbe nbn nbs nbt nbu nbx ne- neb nee nen nes net neu nex nnb nne nnn nns nnt nnu nsb nse nsn nss nst nsu nsx ntb nte ntn nts ntt ntu ntx nub nue nun nus nut nuu nux nxt sbb sbe sbn sbs sbt sbu sbx se- seb see sen ses set seu sex snb sne snn sns snt snu ss- ssb sse ssn sss sst ssu ssx stb ste stn sts stt stu stx sub sue sun sus sut suu sux sxn sxs sxt sxu t-x tbb tbe tbn tbs tbt tbu te- teb tee ten tes tet teu tex tnb tne tnn tns tnt tnx tsb tse tsn tss tst tsu tsx ttb tte ttn tts ttt ttu ttx tub tue tun tus tut tuu tux txe txn txs txt txu ubb ube ubn ubs ubt ubu ubx ueb uee uen ues uet un- unb une unn uns unt unu unx usb use usn uss ust usu usx utb ute utn uts utt utu utx uue uun uus uut uuu uxb uxt uxu xbe xbx xee xen xes xet xeu xex xns xnu xsb xss xst xts xtx xue xun xus xxx