-er b-p bbb bbe bbi bbk bbo bbp bbr bbs bbt be- beb bee bei bek beo bep ber bes bet bi- bib bie bii bik bio bip bir bis bit bkb bke bkk bko bkp bkr bks bkt bob boe boi bok boo bop bor bos bot bpb bpe bpi bpo bpp bpr bps bpt brb bre bri brk bro brp brr brs brt bsb bse bsi bsk bso bsp bsr bss bst btb bte bti btk bto btp btr bts btt ebb ebe ebi ebk ebo ebp ebr ebs ebt eeb eee eek eeo eep eer ees eet eib eie eii eik eio eip eir eis eit ekb eke eki eko ekp ekr eks ekt eo- eob eoe eoi eok eoo eop eor eos eot ep- epb epe epi epo epp epr eps ept erb ere eri erk ero erp err ers ert es- esb ese esi esk eso esp esr ess est etb ete eti etk eto etp etr ets ett ibb ibe ibi ibk ibo ibp ibr ibs ibt ie- iee iei iek iep ier ies iet iib iie iii iio iip iir iis iit ikb ike iki ikk iko ikr iks ikt io- iob ioe ioi ioo iop ior ios iot ipb ipe ipi ipo ipp ipr ips ipt ir- irb ire iri irk iro irp irr irs irt is- isb ise isi isk iso isp isr iss ist itb ite iti itk ito itp its itt k-t kbb kbe kbi kbk kbo kbp kbr kbs ke- keb kee kei kek keo kep ker kes ket kib kie kii kik kio kip kir kis kit kkb kke kki kkk kkp kkr kks kkt kob koe koi kok koo kop kor kos kot kpe kpi kpk kpo kpp kpr kps kpt kri krk kro krp krr krs krt ksb kse ksi ksk kso ksp ksr kss kst ktb kte ktk kto ktp ktr kts ktt o-i ob- obb obe obi obk obo obp obr obs obt oeb oee oei oeo oep oer oes oet oib oie oii oik oio oip oir ois oit okb oke oki okk oko okp okr oks oo- oob ooi ook ooo oop oor oos oot op- opb ope opi opk opo opp opr ops opt or- orb ore ori ork oro orp orr ors ort os- osb ose osi osk oso osp osr oss ost ot- otb ote oti otk oto otp otr ots ott p-p pbb pbe pbi pbk pbo pbp pbr pbs pbt peb pee pei pek peo pep per pes pet pib pie pii pik pio pip pir pis pit pkb pke pki pko pkp pkr pks pkt pob poe poi pok poo pop por pos pot ppb ppe ppi ppk ppo ppp ppr pps ppt prb pre pri prk pro prp prr prs prt ps- psb pse psi psk pso psp psr pss pst pt- ptb pte pti ptk pto ptp ptr pts ptt rbb rbe rbi rbk rbo rbp rbr rbs rbt re- reb ree rei rek reo rep rer res ret rib rie rii rik rio rip rir ris rit rkb rke rkk rko rkp rks rkt rob roe roi rok roo rop ror ros rot rpb rpe rpi rpk rpo rpp rpr rps rpt rrb rri rrk rrp rrr rrs rrt rsb rse rsi rsk rso rsp rsr rss rst rtb rte rti rtk rto rtp rtr rts rtt sbb sbe sbi sbk sbo sbp sbr sbs sbt se- seb see sei sek seo sep ser ses set sib sie sii sik sio sip sir sis sit sk- skb ske ski skk sko skp skr sks skt sob soe soi sok soo sop sor sos sot spb spe spi spk spo spp spr sps spt sr- srb sre sri srk sro srp srr srs srt ss- ssb sse ssi ssk sso ssp ssr sss sst stb ste sti stk sto stp str sts stt tbb tbe tbi tbk tbo tbp tbr tbs tbt te- teb tee tei tek teo tep ter tes tet tib tie tii tik tio tip tir tis tit tkb tke tkk tko tkp tkr tks tkt to- tob toe toi tok too top tor tos tot tpb tpe tpi tpk tpo tpp tpr tps tpt trb tre tri trk tro trp trr trs trt tsb tse tsi tsk tso tsp tsr tss tst ttb tte tti ttk tto ttp ttr tts ttt