-er b-p bbb bbc bbe bbo bbp bbr bbs bbt bcb bcc bce bco bcp bcr bcs bct be- beb bec bee beo bep ber bes bet bob boc boe boo bop bor bos bot bpb bpc bpe bpo bpp bpr bps bpt brb bre bro brp brr brs brt bsb bsc bse bso bsp bsr bss bst btb btc bte bto btp btr bts btt c-- cbb cbc cbe cbo cbp cbr cbs cbt ccb ccc cce cco ccp ccr ccs cct ce- ceb cec cee ceo cep cer ces cet co- cob coc coe coo cop cor cos cot cpb cpc cpe cpo cpp cpr cps cpt crb crc cre cro crp crr crs crt csb csc cse cso csp csr css cst ctb ctc cte cto ctp ctr cts ctt ebb ebc ebe ebo ebp ebr ebs ebt ec- ecb ecc ece eco ecr ecs ect eeb eec eee eeo eep eer ees eet eo- eob eoc eoe eoo eop eor eos eot ep- epb epc epe epo epp epr eps ept erb erc ere ero erp err ers ert es- esb esc ese eso esp esr ess est etb etc ete eto etp etr ets ett ob- obb obc obe obo obp obr obs obt oc- ocb occ oco ocp ocr ocs oct oeb oec oee oeo oep oer oes oet oo- oob ooc ooo oop oor oos oot op- opb opc ope opo opp opr ops opt or- orb orc ore oro orp orr ors ort os- osb osc ose oso osp osr oss ost ot- otb otc ote oto otp otr ots ott p-p pbb pbc pbe pbo pbp pbr pbs pbt pcb pcc pce pco pcp pcr pcs pct peb pec pee peo pep per pes pet pob poc poe poo pop por pos pot ppb ppc ppe ppo ppp ppr pps ppt prb prc pre pro prp prr prs prt ps- psb psc pse pso psp psr pss pst pt- ptb ptc pte pto ptp ptr pts ptt rbb rbc rbe rbo rbp rbr rbs rbt rcb rcc rce rco rcp rcr rcs rct re- reb rec ree reo rep rer res ret rob roc roe roo rop ror ros rot rpb rpc rpe rpo rpp rpr rps rpt rrb rrc rrp rrr rrs rrt rsb rsc rse rso rsp rsr rss rst rtb rtc rte rto rtp rtr rts rtt sbb sbc sbe sbo sbp sbr sbs sbt scb scc sce sco scp scr scs sct se- seb sec see seo sep ser ses set sob soc soe soo sop sor sos sot spb spc spe spo spp spr sps spt sr- srb src sre sro srp srr srs srt ss- ssb ssc sse sso ssp ssr sss sst stb stc ste sto stp str sts stt tbb tbc tbe tbo tbp tbr tbs tbt tcb tcc tce tco tcp tcr tcs tct te- teb tec tee teo tep ter tes tet to- tob toc toe too top tor tos tot tpb tpc tpe tpo tpp tpr tps tpt trb trc tre tro trp trr trs trt tsb tsc tse tso tsp tsr tss tst ttb ttc tte tto ttp ttr tts ttt