-er b-p bbb bbe bbk bbo bbp bbr bbs bbt be- beb bee bek beo bep ber bes bet bkb bke bkk bko bkp bkr bks bkt bob boe bok boo bop bor bos bot bpb bpe bpo bpp bpr bps bpt brb bre brk bro brp brr brs brt bsb bse bsk bso bsp bsr bss bst btb bte btk bto btp btr bts btt ebb ebe ebk ebo ebp ebr ebs ebt eeb eee eek eeo eep eer ees eet ekb eke eko ekp ekr eks ekt eo- eob eoe eok eoo eop eor eos eot ep- epb epe epo epp epr eps ept erb ere erk ero erp err ers ert es- esb ese esk eso esp esr ess est etb ete etk eto etp etr ets ett k-t kbb kbe kbk kbo kbp kbr kbs ke- keb kee kek keo kep ker kes ket kkb kke kkk kkp kkr kks kkt kob koe kok koo kop kor kos kot kpe kpk kpo kpp kpr kps kpt krk kro krp krr krs krt ksb kse ksk kso ksp ksr kss kst ktb kte ktk kto ktp ktr kts ktt ob- obb obe obk obo obp obr obs obt oeb oee oeo oep oer oes oet okb oke okk oko okp okr oks oo- oob ook ooo oop oor oos oot op- opb ope opk opo opp opr ops opt or- orb ore ork oro orp orr ors ort os- osb ose osk oso osp osr oss ost ot- otb ote otk oto otp otr ots ott p-p pbb pbe pbk pbo pbp pbr pbs pbt peb pee pek peo pep per pes pet pkb pke pko pkp pkr pks pkt pob poe pok poo pop por pos pot ppb ppe ppk ppo ppp ppr pps ppt prb pre prk pro prp prr prs prt ps- psb pse psk pso psp psr pss pst pt- ptb pte ptk pto ptp ptr pts ptt rbb rbe rbk rbo rbp rbr rbs rbt re- reb ree rek reo rep rer res ret rkb rke rkk rko rkp rks rkt rob roe rok roo rop ror ros rot rpb rpe rpk rpo rpp rpr rps rpt rrb rrk rrp rrr rrs rrt rsb rse rsk rso rsp rsr rss rst rtb rte rtk rto rtp rtr rts rtt sbb sbe sbk sbo sbp sbr sbs sbt se- seb see sek seo sep ser ses set sk- skb ske skk sko skp skr sks skt sob soe sok soo sop sor sos sot spb spe spk spo spp spr sps spt sr- srb sre srk sro srp srr srs srt ss- ssb sse ssk sso ssp ssr sss sst stb ste stk sto stp str sts stt tbb tbe tbk tbo tbp tbr tbs tbt te- teb tee tek teo tep ter tes tet tkb tke tkk tko tkp tkr tks tkt to- tob toe tok too top tor tos tot tpb tpe tpk tpo tpp tpr tps tpt trb tre trk tro trp trr trs trt tsb tse tsk tso tsp tsr tss tst ttb tte ttk tto ttp ttr tts ttt