-er b-p bbb bbe bbm bbo bbp bbr bbt bbx be- beb bee bem beo bep ber bet bex bmb bme bmm bmo bmp bmr bmt bmx bob boe bom boo bop bor bot box bpb bpe bpm bpo bpp bpr bpt bpx brb bre brm bro brp brr brt brx btb bte btm bto btp btr btt btx bxb bxm bxo bxx ebb ebe ebm ebo ebp ebr ebt ebx eeb eee eem eeo eep eer eet eex em- emb eme emm emo emp emr emt emx eo- eob eoe eom eoo eop eor eot ep- epb epe epm epo epp epr ept epx erb ere erm ero erp err ert etb ete etm eto etp etr ett etx ex- exe exo exp exr ext exx m-o m-r mbb mbe mbm mbo mbp mbr mbt mbx meb mee mem meo mep mer met mex mmb mme mmm mmo mmp mmr mmt mmx mob moe mom moo mop mor mot mox mpb mpe mpm mpo mpp mpr mpt mpx mrb mre mrm mro mrp mrr mrt mrx mtb mte mtm mto mtp mtr mtt mtx mxp mxr ob- obb obe obm obo obp obr obt obx oeb oee oem oeo oep oer oet oex om- omb ome omm omo omp omr omt omx oo- oob oom ooo oop oor oot oox op- opb ope opm opo opp opr opt opx or- orb ore orm oro orp orr ort orx ot- otb ote otm oto otp otr ott ox- oxb oxo oxt oxx p-p pbb pbe pbm pbo pbp pbr pbt pbx peb pee pem peo pep per pet pex pmb pme pmm pmo pmp pmr pmt pmx pob poe pom poo pop por pot pox ppb ppe ppm ppo ppp ppr ppt ppx prb pre prm pro prp prr prt prx pt- ptb pte ptm pto ptp ptr ptt ptx pxe pxm pxr pxt rbb rbe rbm rbo rbp rbr rbt rbx re- reb ree rem reo rep rer ret rex rmb rme rmm rmo rmp rmr rmt rmx rob roe rom roo rop ror rot rox rpb rpe rpm rpo rpp rpr rpt rpx rrb rrm rrp rrr rrt rtb rte rtm rto rtp rtr rtt rtx rxp rxr t-x tbb tbe tbm tbo tbp tbr tbt te- teb tee tem teo tep ter tet tex tmb tme tmm tmo tmp tmr tmt tmx to- tob toe tom too top tor tot tox tpb tpe tpm tpo tpp tpr tpt tpx trb tre trm tro trp trr trt trx ttb tte ttm tto ttp ttr ttt ttx txe txt xbe xbr xbx xee xem xep xer xet xex xmm xmo xmp xmr xmt xmx xom xoo xop xor xot xox xpb xpe xpm xpo xpp xpt xrt xrx xtm xtp xtr xtx xxo xxp xxx