-er b-p bbb bbc bbe bbk bbp bbr bbs bbt bcb bcc bce bck bcp bcr bcs bct be- beb bec bee bek bep ber bes bet bkb bkc bke bkk bkp bkr bks bkt bpb bpc bpe bpp bpr bps bpt brb bre brk brp brr brs brt bsb bsc bse bsk bsp bsr bss bst btb btc bte btk btp btr bts btt c-- cbb cbc cbe cbk cbp cbr cbs cbt ccb ccc cce cck ccp ccr ccs cct ce- ceb cec cee cek cep cer ces cet ckb ckc cks ckt cpb cpc cpe cpk cpp cpr cps cpt crb crc cre crk crp crr crs crt csb csc cse csk csp csr css cst ctb ctc cte ctk ctp ctr cts ctt ebb ebc ebe ebk ebp ebr ebs ebt ec- ecb ecc ece eck ecr ecs ect eeb eec eee eek eep eer ees eet ekb ekc eke ekp ekr eks ekt ep- epb epc epe epp epr eps ept erb erc ere erk erp err ers ert es- esb esc ese esk esp esr ess est etb etc ete etk etp etr ets ett k-t kbb kbc kbe kbk kbp kbr kbs kcb kcc kce kck kcp kcr kcs kct ke- keb kec kee kek kep ker kes ket kkb kkc kke kkk kkp kkr kks kkt kpc kpe kpk kpp kpr kps kpt krc krk krp krr krs krt ksb ksc kse ksk ksp ksr kss kst ktb ktc kte ktk ktp ktr kts ktt p-p pbb pbc pbe pbk pbp pbr pbs pbt pcb pcc pce pck pcp pcr pcs pct peb pec pee pek pep per pes pet pkb pkc pke pkp pkr pks pkt ppb ppc ppe ppk ppp ppr pps ppt prb prc pre prk prp prr prs prt ps- psb psc pse psk psp psr pss pst pt- ptb ptc pte ptk ptp ptr pts ptt rbb rbc rbe rbk rbp rbr rbs rbt rcb rcc rce rcp rcr rcs rct re- reb rec ree rek rep rer res ret rkb rkc rke rkk rkp rks rkt rpb rpc rpe rpk rpp rpr rps rpt rrb rrc rrk rrp rrr rrs rrt rsb rsc rse rsk rsp rsr rss rst rtb rtc rte rtk rtp rtr rts rtt sbb sbc sbe sbk sbp sbr sbs sbt scb scc sce sck scp scr scs sct se- seb sec see sek sep ser ses set sk- skb skc ske skk skp skr sks skt spb spc spe spk spp spr sps spt sr- srb src sre srk srp srr srs srt ss- ssb ssc sse ssk ssp ssr sss sst stb stc ste stk stp str sts stt tbb tbc tbe tbk tbp tbr tbs tbt tcb tcc tce tck tcp tcr tcs tct te- teb tec tee tek tep ter tes tet tkb tkc tke tkk tkp tkr tks tkt tpb tpc tpe tpk tpp tpr tps tpt trb trc tre trk trp trr trs trt tsb tsc tse tsk tsp tsr tss tst ttb ttc tte ttk ttp ttr tts ttt