-er a-a a-b a-c aaa aab aac aad aae aam aao aar ab- aba abb abc abd abe abm abo abr ac- aca acb acc acd ace acm aco acr ad- ada adb adc add ade adm ado adr aea aeb aec aed aee aem aeo aer ama amb amc amd ame amm amo amr aoa aob aoc aod aoe aom aoo aor ar- ara arb arc ard are arm aro arr baa bab bac bad bae bam bao bar bba bbb bbc bbd bbe bbm bbo bbr bca bcb bcc bcd bce bcm bco bcr bda bdb bdc bdd bde bdm bdo bdr be- bea beb bec bed bee bem beo ber bma bmb bmc bmd bme bmm bmo bmr boa bob boc bod boe bom boo bor bra brb brd bre brm bro brr c-- caa cab cac cad cae cam cao car cba cbb cbc cbd cbe cbm cbo cbr cca ccb ccc ccd cce ccm cco ccr cda cdb cdc cdd cde cdm cdo cdr ce- cea ceb cec ced cee cem ceo cer cma cmb cmc cmd cme cmm cmo cmr co- coa cob coc cod coe com coo cor cra crb crc crd cre crm cro crr daa dab dac dad dae dam dao dar dba dbb dbc dbd dbe dbm dbo dbr dca dcb dcc dcd dce dcm dco dcr dda ddb ddc ddd dde ddm ddo ddr de- dea deb dec ded dee dem deo der dma dmb dmc dmd dme dmm dmo dmr doa dob doc dod doe dom doo dor dra drb drc drd dre drm dro drr eaa eab eac ead eae eam eao ear eba ebb ebc ebd ebe ebm ebo ebr ec- eca ecb ecc ecd ece ecm eco ecr ed- eda edb edc edd ede edm edo edr eea eeb eec eed eee eem eeo eer em- ema emb emc emd eme emm emo emr eo- eoa eob eoc eod eoe eom eoo eor era erb erc erd ere erm ero err m-o m-r maa mab mac mad mae mam mao mar mba mbb mbc mbd mbe mbm mbo mbr mc- mca mcb mcc mcd mce mcm mco mcr mda mdb mdc mdd mde mdm mdo mdr mea meb mec med mee mem meo mer mma mmb mmc mmd mme mmm mmo mmr moa mob moc mod moe mom moo mor mra mrb mrc mrd mre mrm mro mrr oaa oab oac oad oae oam oao oar ob- oba obb obc obd obe obm obo obr oc- oca ocb occ ocd ocm oco ocr oda odb odc odd ode odm odo odr oea oeb oec oed oee oem oeo oer om- oma omb omc omd ome omm omo omr oo- ooa oob ooc ood oom ooo oor or- ora orb orc ord ore orm oro orr ra- raa rab rac rad rae ram rao rar rba rbb rbc rbd rbe rbm rbo rbr rca rcb rcc rcd rce rcm rco rcr rda rdb rdc rdd rde rdm rdo rdr re- rea reb rec red ree rem reo rer rma rmb rmc rmd rme rmm rmo rmr roa rob roc rod roe rom roo ror rra rrb rrc rrd rrm rrr