-er b-u bbb bbc bbd bbe bbr bbs bbt bbu bcb bcc bcd bce bcr bcs bct bcu bdb bdc bdd bde bdr bds bdt bdu be- beb bec bed bee ber bes bet beu brb brd bre brr brs brt bru bsb bsc bsd bse bsr bss bst bsu btb btc btd bte btr bts btt btu bub buc bud bue bur bus but buu c-- cbb cbc cbd cbe cbr cbs cbt cbu ccb ccc ccd cce ccr ccs cct ccu cdb cdc cdd cde cdr cds cdt cdu ce- ceb cec ced cee cer ces cet ceu crb crc crd cre crr crs crt cru csb csc csd cse csr css cst csu ctb ctc ctd cte ctr cts ctt ctu cub cuc cud cue cur cus cut cuu dbb dbc dbd dbe dbr dbs dbt dbu dcb dcc dcd dce dcr dcs dct dcu ddb ddc ddd dde ddr dds ddt ddu de- deb dec ded dee der des det deu drb drc drd dre drr drs drt dru dsb dsc dsd dse dsr dss dst dsu dtb dtc dtd dte dtr dts dtt dtu dub duc dud due dur dus dut ebb ebc ebd ebe ebr ebs ebt ebu ec- ecb ecc ecd ece ecr ecs ect ecu ed- edb edc edd ede edr eds edt edu eeb eec eed eee eer ees eet erb erc erd ere err ers ert eru es- esb esc esd ese esr ess est esu etb etc etd ete etr ets ett etu eu- eub euc eud eue eur eus eut rbb rbc rbd rbe rbr rbs rbt rbu rcb rcc rcd rce rcr rcs rct rcu rdb rdc rdd rde rdr rds rdt rdu re- reb rec red ree rer res ret reu rrb rrc rrd rrr rrs rrt rru rsb rsc rsd rse rsr rss rst rsu rtb rtc rtd rte rtr rts rtt rtu rub ruc rud rue rur rus rut ruu sbb sbc sbd sbe sbr sbs sbt sbu scb scc scd sce scr scs sct scu sdb sdc sdd sde sdr sds sdt sdu se- seb sec sed see ser ses set seu sr- srb src srd sre srr srs srt ss- ssb ssc ssd sse ssr sss sst ssu stb stc std ste str sts stt stu sub suc sud sue sur sus sut suu tbb tbc tbd tbe tbr tbs tbt tbu tcb tcc tcd tce tcr tcs tct tcu tdb tdc tdd tde tdr tds tdt tdu te- teb tec ted tee ter tes tet teu trb trc trd tre trr trs trt tru tsb tsc tsd tse tsr tss tst tsu ttb ttc ttd tte ttr tts ttt ttu tub tuc tud tue tur tus tut tuu ubb ubc ube ubr ubs ubt ubu ucb ucc ucd uce ucr ucs uct ucu udb udc udd ude udr uds udt udu ueb uec ued uee uer ues uet ur- urb urc urd ure urr urs urt uru usb usc usd use usr uss ust usu utb utc utd ute utr uts utt utu uuc uue uur uus uut uuu