-er bbb bbc bbd bbe bbm bbr bcb bcc bcd bce bcm bcr bdb bdc bdd bde bdm bdr be- beb bec bed bee bem ber bmb bmc bmd bme bmm bmr brb brd bre brm brr c-- cbb cbc cbd cbe cbm cbr ccb ccc ccd cce ccm ccr cdb cdc cdd cde cdm cdr ce- ceb cec ced cee cem cer cmb cmc cmd cme cmm cmr crb crc crd cre crm crr dbb dbc dbd dbe dbm dbr dcb dcc dcd dce dcm dcr ddb ddc ddd dde ddm ddr de- deb dec ded dee dem der dmb dmc dmd dme dmm dmr drb drc drd dre drm drr ebb ebc ebd ebe ebm ebr ec- ecb ecc ecd ece ecm ecr ed- edb edc edd ede edm edr eeb eec eed eee eem eer em- emb emc emd eme emm emr erb erc erd ere erm err m-r mbb mbc mbd mbe mbm mbr mc- mcb mcc mcd mce mcm mcr mdb mdc mdd mde mdm mdr meb mec med mee mem mer mmb mmc mmd mme mmm mmr mrb mrc mrd mre mrm mrr rbb rbc rbd rbe rbm rbr rcb rcc rcd rce rcm rcr rdb rdc rdd rde rdm rdr re- reb rec red ree rem rer rmb rmc rmd rme rmm rmr rrb rrc rrd rrm rrr