b-u bbb bbe bbi bbs bbt bbu bbx be- beb bee bei bes bet beu bex bi- bib bie bii bis bit biu bix bsb bse bsi bss bst bsu bsx btb bte bti bts btt btu btx bub bue bui bus but buu bux bxb bxi bxx ebb ebe ebi ebs ebt ebu ebx eeb eee ees eet eex eib eie eii eis eit eiu eix es- esb ese esi ess est esu esx etb ete eti ets ett etu etx eu- eub eue eui eus eut eux ex- exe exi exs ext exu exx ibb ibe ibi ibs ibt ibu ibx ie- iee iei ies iet iex iib iie iii iis iit iiu iix is- isb ise isi iss ist isu itb ite iti its itt itu itx iu- iub iue iui ius iut ixe ixi sbb sbe sbi sbs sbt sbu sbx se- seb see sei ses set seu sex sib sie sii sis sit siu six ss- ssb sse ssi sss sst ssu ssx stb ste sti sts stt stu stx sub sue sui sus sut suu sux sxi sxs sxt sxu t-x tbb tbe tbi tbs tbt tbu te- teb tee tei tes tet teu tex tib tie tii tis tit tiu tix tsb tse tsi tss tst tsu tsx ttb tte tti tts ttt ttu ttx tub tue tui tus tut tuu tux txe txi txs txt txu ubb ube ubi ubs ubt ubu ubx ueb uee uei ues uet uib uie uii uis uit uiu usb use usi uss ust usu usx utb ute uti uts utt utu utx uue uus uut uuu uxb uxt uxu xbe xbx xee xes xet xeu xex xie xii xis xit xiu xix xsb xsi xss xst xti xts xtx xue xui xus xxi xxx