-er b-p bbb bbe bbi bbo bbp bbr bbt be- beb bee bei beo bep ber bet bi- bib bie bii bio bip bir bit bob boe boi boo bop bor bot bpb bpe bpi bpo bpp bpr bpt brb bre bri bro brp brr brt btb bte bti bto btp btr btt ebb ebe ebi ebo ebp ebr ebt eeb eee eeo eep eer eet eib eie eii eio eip eir eit eo- eob eoe eoi eoo eop eor eot ep- epb epe epi epo epp epr ept erb ere eri ero erp err ert etb ete eti eto etp etr ett ibb ibe ibi ibo ibp ibr ibt ie- iee iei iep ier iet iib iie iii iio iip iir iit io- iob ioe ioi ioo iop ior iot ipb ipe ipi ipo ipp ipr ipt ir- irb ire iri iro irp irr irt itb ite iti ito itp itt o-i ob- obb obe obi obo obp obr obt oeb oee oei oeo oep oer oet oib oie oii oio oip oir oit oo- oob ooi ooo oop oor oot op- opb ope opi opo opp opr opt or- orb ore ori oro orp orr ort ot- otb ote oti oto otp otr ott p-p pbb pbe pbi pbo pbp pbr pbt peb pee pei peo pep per pet pib pie pii pio pip pir pit pob poe poi poo pop por pot ppb ppe ppi ppo ppp ppr ppt prb pre pri pro prp prr prt pt- ptb pte pti pto ptp ptr ptt rbb rbe rbi rbo rbp rbr rbt re- reb ree rei reo rep rer ret rib rie rii rio rip rir rit rob roe roi roo rop ror rot rpb rpe rpi rpo rpp rpr rpt rrb rri rrp rrr rrt rtb rte rti rto rtp rtr rtt tbb tbe tbi tbo tbp tbr tbt te- teb tee tei teo tep ter tet tib tie tii tio tip tir tit to- tob toe toi too top tor tot tpb tpe tpi tpo tpp tpr tpt trb tre tri tro trp trr trt ttb tte tti tto ttp ttr ttt