-er bbb bbe bbk bbn bbo bbr bbs bbt be- beb bee bek ben beo ber bes bet bkb bke bkk bkn bko bkr bks bkt bnb bne bnk bnn bno bnr bns bnt bob boe bok bon boo bor bos bot brb bre brk brn bro brr brs brt bsb bse bsk bsn bso bsr bss bst btb bte btk btn bto btr bts btt ebb ebe ebk ebn ebo ebr ebs ebt eeb eee eek een eeo eer ees eet ekb eke eko ekr eks ekt en- enb ene enk enn eno enr ens ent eo- eob eoe eok eon eoo eor eos eot erb ere erk ern ero err ers ert es- esb ese esk esn eso esr ess est etb ete etk etn eto etr ets ett k-t kbb kbe kbk kbn kbo kbr kbs ke- keb kee kek ken keo ker kes ket kkb kke kkk kkn kkr kks kkt kn- kne knk knn kno knr knt kob koe kok kon koo kor kos kot krk krn kro krr krs krt ksb kse ksk ksn kso ksr kss kst ktb kte ktk ktn kto ktr kts ktt nbb nbe nbk nbn nbo nbr nbs nbt ne- neb nee nek nen neo ner nes net nke nkk nkn nko nkr nks nkt nnb nne nnk nnn nno nns nnt no- nob noe nok non noo nor nos not nrb nre nrk nrn nro nrr nrs nrt nsb nse nsk nsn nso nsr nss nst ntb nte ntk ntn nto ntr nts ntt ob- obb obe obk obn obo obr obs obt oeb oee oen oeo oer oes oet okb oke okk oko okr oks on- onb one onk onn ono onr ons ont oo- oob ook oon ooo oor oos oot or- orb ore ork orn oro orr ors ort os- osb ose osk osn oso osr oss ost ot- otb ote otk otn oto otr ots ott rbb rbe rbk rbn rbo rbr rbs rbt re- reb ree rek ren reo rer res ret rkb rke rkk rko rks rkt rnb rnn rno rnr rns rnt rob roe rok ron roo ror ros rot rrb rrk rrn rrr rrs rrt rsb rse rsk rsn rso rsr rss rst rtb rte rtk rtn rto rtr rts rtt sbb sbe sbk sbn sbo sbr sbs sbt se- seb see sek sen seo ser ses set sk- skb ske skk sko skr sks skt snb sne snk snn sno snr sns snt sob soe sok son soo sor sos sot sr- srb sre srk srn sro srr srs srt ss- ssb sse ssk ssn sso ssr sss sst stb ste stk stn sto str sts stt tbb tbe tbk tbn tbo tbr tbs tbt te- teb tee tek ten teo ter tes tet tkb tke tkk tko tkr tks tkt tnb tne tnk tnn tno tnr tns tnt to- tob toe tok ton too tor tos tot trb tre trk trn tro trr trs trt tsb tse tsk tsn tso tsr tss tst ttb tte ttk ttn tto ttr tts ttt