a-a a-b a-c aaa aab aac aad aam aao aar ab- aba abb abc abd abm abo abr ac- aca acb acc acd acm aco acr ad- ada adb adc add adm ado adr ama amb amc amd amm amo amr aoa aob aoc aod aom aoo aor ar- ara arb arc ard arm aro arr baa bab bac bad bam bao bar bba bbb bbc bbd bbm bbo bbr bca bcb bcc bcd bcm bco bcr bda bdb bdc bdd bdm bdo bdr bma bmb bmc bmd bmm bmo bmr boa bob boc bod bom boo bor bra brb brd brm bro brr c-- caa cab cac cad cam cao car cba cbb cbc cbd cbm cbo cbr cca ccb ccc ccd ccm cco ccr cda cdb cdc cdd cdm cdo cdr cma cmb cmc cmd cmm cmo cmr co- coa cob coc cod com coo cor cra crb crc crd crm cro crr daa dab dac dad dam dao dar dba dbb dbc dbd dbm dbo dbr dca dcb dcc dcd dcm dco dcr dda ddb ddc ddd ddm ddo ddr dma dmb dmc dmd dmm dmo dmr doa dob doc dod dom doo dor dra drb drc drd drm dro drr m-o m-r maa mab mac mad mam mao mar mba mbb mbc mbd mbm mbo mbr mc- mca mcb mcc mcd mcm mco mcr mda mdb mdc mdd mdm mdo mdr mma mmb mmc mmd mmm mmo mmr moa mob moc mod mom moo mor mra mrb mrc mrd mrm mro mrr oaa oab oac oad oam oao oar ob- oba obb obc obd obm obo obr oc- oca ocb occ ocd ocm oco ocr oda odb odc odd odm odo odr om- oma omb omc omd omm omo omr oo- ooa oob ooc ood oom ooo oor or- ora orb orc ord orm oro orr ra- raa rab rac rad ram rao rar rba rbb rbc rbd rbm rbo rbr rca rcb rcc rcd rcm rco rcr rda rdb rdc rdd rdm rdo rdr rma rmb rmc rmd rmm rmo rmr roa rob roc rod rom roo ror rra rrb rrc rrd rrm rrr