-er b-p bbb bbe bbi bbo bbp bbr bbs bbt be- beb bee bei beo bep ber bes bet bi- bib bie bii bio bip bir bis bit bob boe boi boo bop bor bos bot bpb bpe bpi bpo bpp bpr bps bpt brb bre bri bro brp brr brs brt bsb bse bsi bso bsp bsr bss bst btb bte bti bto btp btr bts btt ebb ebe ebi ebo ebp ebr ebs ebt eeb eee eeo eep eer ees eet eib eie eii eio eip eir eis eit eo- eob eoe eoi eoo eop eor eos eot ep- epb epe epi epo epp epr eps ept erb ere eri ero erp err ers ert es- esb ese esi eso esp esr ess est etb ete eti eto etp etr ets ett ibb ibe ibi ibo ibp ibr ibs ibt ie- iee iei iep ier ies iet iib iie iii iio iip iir iis iit io- iob ioe ioi ioo iop ior ios iot ipb ipe ipi ipo ipp ipr ips ipt ir- irb ire iri iro irp irr irs irt is- isb ise isi iso isp isr iss ist itb ite iti ito itp its itt o-i ob- obb obe obi obo obp obr obs obt oeb oee oei oeo oep oer oes oet oib oie oii oio oip oir ois oit oo- oob ooi ooo oop oor oos oot op- opb ope opi opo opp opr ops opt or- orb ore ori oro orp orr ors ort os- osb ose osi oso osp osr oss ost ot- otb ote oti oto otp otr ots ott p-p pbb pbe pbi pbo pbp pbr pbs pbt peb pee pei peo pep per pes pet pib pie pii pio pip pir pis pit pob poe poi poo pop por pos pot ppb ppe ppi ppo ppp ppr pps ppt prb pre pri pro prp prr prs prt ps- psb pse psi pso psp psr pss pst pt- ptb pte pti pto ptp ptr pts ptt rbb rbe rbi rbo rbp rbr rbs rbt re- reb ree rei reo rep rer res ret rib rie rii rio rip rir ris rit rob roe roi roo rop ror ros rot rpb rpe rpi rpo rpp rpr rps rpt rrb rri rrp rrr rrs rrt rsb rse rsi rso rsp rsr rss rst rtb rte rti rto rtp rtr rts rtt sbb sbe sbi sbo sbp sbr sbs sbt se- seb see sei seo sep ser ses set sib sie sii sio sip sir sis sit sob soe soi soo sop sor sos sot spb spe spi spo spp spr sps spt sr- srb sre sri sro srp srr srs srt ss- ssb sse ssi sso ssp ssr sss sst stb ste sti sto stp str sts stt tbb tbe tbi tbo tbp tbr tbs tbt te- teb tee tei teo tep ter tes tet tib tie tii tio tip tir tis tit to- tob toe toi too top tor tos tot tpb tpe tpi tpo tpp tpr tps tpt trb tre tri tro trp trr trs trt tsb tse tsi tso tsp tsr tss tst ttb tte tti tto ttp ttr tts ttt