-er b-p bbb bbc bbd bbe bbo bbp bbr bbs bcb bcc bcd bce bco bcp bcr bcs bdb bdc bdd bde bdo bdp bdr bds be- beb bec bed bee beo bep ber bes bob boc bod boe boo bop bor bos bpb bpc bpd bpe bpo bpp bpr bps brb brd bre bro brp brr brs bsb bsc bsd bse bso bsp bsr bss c-- cbb cbc cbd cbe cbo cbp cbr cbs ccb ccc ccd cce cco ccp ccr ccs cdb cdc cdd cde cdo cdp cdr cds ce- ceb cec ced cee ceo cep cer ces co- cob coc cod coe coo cop cor cos cpb cpc cpd cpe cpo cpp cpr cps crb crc crd cre cro crp crr crs csb csc csd cse cso csp csr css dbb dbc dbd dbe dbo dbp dbr dbs dcb dcc dcd dce dco dcp dcr dcs ddb ddc ddd dde ddo ddp ddr dds de- deb dec ded dee deo dep der des dob doc dod doe doo dop dor dos dpb dpc dpd dpe dpo dpp dpr dps drb drc drd dre dro drp drr drs dsb dsc dsd dse dso dsp dsr dss ebb ebc ebd ebe ebo ebp ebr ebs ec- ecb ecc ecd ece eco ecr ecs ed- edb edc edd ede edo edp edr eds eeb eec eed eee eeo eep eer ees eo- eob eoc eod eoe eoo eop eor eos ep- epb epc epd epe epo epp epr eps erb erc erd ere ero erp err ers es- esb esc esd ese eso esp esr ess ob- obb obc obd obe obo obp obr obs oc- ocb occ ocd oco ocp ocr ocs odb odc odd ode odo odp odr ods oeb oec oed oee oeo oep oer oes oo- oob ooc ood ooo oop oor oos op- opb opc opd ope opo opp opr ops or- orb orc ord ore oro orp orr ors os- osb osc osd ose oso osp osr oss p-p pbb pbc pbd pbe pbo pbp pbr pbs pcb pcc pcd pce pco pcp pcr pcs pdb pdc pdd pde pdo pdp pdr pds peb pec ped pee peo pep per pes pob poc pod poe poo pop por pos ppb ppc ppd ppe ppo ppp ppr pps prb prc prd pre pro prp prr prs ps- psb psc psd pse pso psp psr pss rbb rbc rbd rbe rbo rbp rbr rbs rcb rcc rcd rce rco rcp rcr rcs rdb rdc rdd rde rdo rdp rdr rds re- reb rec red ree reo rep rer res rob roc rod roe roo rop ror ros rpb rpc rpd rpe rpo rpp rpr rps rrb rrc rrd rrp rrr rrs rsb rsc rsd rse rso rsp rsr rss sbb sbc sbd sbe sbo sbp sbr sbs scb scc scd sce sco scp scr scs sdb sdc sdd sde sdo sdp sdr sds se- seb sec sed see seo sep ser ses sob soc sod soe soo sop sor sos spb spc spd spe spo spp spr sps sr- srb src srd sre sro srp srr srs ss- ssb ssc ssd sse sso ssp ssr sss