bbb bbe bbi bbo bbs bbt bbx be- beb bee bei beo bes bet bex bi- bib bie bii bio bis bit bix bob boe boi boo bos bot box bsb bse bsi bso bss bst bsx btb bte bti bto bts btt btx bxb bxi bxo bxx ebb ebe ebi ebo ebs ebt ebx eeb eee eeo ees eet eex eib eie eii eio eis eit eix eo- eob eoe eoi eoo eos eot es- esb ese esi eso ess est esx etb ete eti eto ets ett etx ex- exe exi exo exs ext exx ibb ibe ibi ibo ibs ibt ibx ie- iee iei ies iet iex iib iie iii iio iis iit iix io- iob ioe ioi ioo ios iot is- isb ise isi iso iss ist itb ite iti ito its itt itx ixe ixi o-i ob- obb obe obi obo obs obt obx oeb oee oei oeo oes oet oex oib oie oii oio ois oit oo- oob ooi ooo oos oot oox os- osb ose osi oso oss ost osx ot- otb ote oti oto ots ott ox- oxb oxi oxo oxt oxx sbb sbe sbi sbo sbs sbt sbx se- seb see sei seo ses set sex sib sie sii sio sis sit six sob soe soi soo sos sot sox ss- ssb sse ssi sso sss sst ssx stb ste sti sto sts stt stx sxi sxs sxt t-x tbb tbe tbi tbo tbs tbt te- teb tee tei teo tes tet tex tib tie tii tio tis tit tix to- tob toe toi too tos tot tox tsb tse tsi tso tss tst tsx ttb tte tti tto tts ttt ttx txe txi txs txt xbe xbx xee xes xet xex xie xii xio xis xit xix xoi xoo xos xot xox xsb xsi xss xst xti xts xtx xxi xxo xxx