-er a-a a-b a-c aaa aab aac aad aae aao aap aar aas ab- aba abb abc abd abe abo abp abr abs ac- aca acb acc acd ace aco acp acr acs ad- ada adb adc add ade ado adp adr ads aea aeb aec aed aee aeo aep aer aes aoa aob aoc aod aoe aoo aop aor aos ap- apa apb apc apd ape apo app apr aps ar- ara arb arc ard are aro arp arr ars as- asa asb asc asd ase aso asp asr ass b-p baa bab bac bad bae bao bap bar bas bba bbb bbc bbd bbe bbo bbp bbr bbs bca bcb bcc bcd bce bco bcp bcr bcs bda bdb bdc bdd bde bdo bdp bdr bds be- bea beb bec bed bee beo bep ber bes boa bob boc bod boe boo bop bor bos bpa bpb bpc bpd bpe bpo bpp bpr bps bra brb brd bre bro brp brr brs bsa bsb bsc bsd bse bso bsp bsr bss c-- caa cab cac cad cae cao cap car cas cba cbb cbc cbd cbe cbo cbp cbr cbs cca ccb ccc ccd cce cco ccp ccr ccs cda cdb cdc cdd cde cdo cdp cdr cds ce- cea ceb cec ced cee ceo cep cer ces co- coa cob coc cod coe coo cop cor cos cpa cpb cpc cpd cpe cpo cpp cpr cps cra crb crc crd cre cro crp crr crs csa csb csc csd cse cso csp csr css daa dab dac dad dae dao dap dar das dba dbb dbc dbd dbe dbo dbp dbr dbs dca dcb dcc dcd dce dco dcp dcr dcs dda ddb ddc ddd dde ddo ddp ddr dds de- dea deb dec ded dee deo dep der des doa dob doc dod doe doo dop dor dos dpa dpb dpc dpd dpe dpo dpp dpr dps dra drb drc drd dre dro drp drr drs dsa dsb dsc dsd dse dso dsp dsr dss eaa eab eac ead eae eao eap ear eas eba ebb ebc ebd ebe ebo ebp ebr ebs ec- eca ecb ecc ecd ece eco ecr ecs ed- eda edb edc edd ede edo edp edr eds eea eeb eec eed eee eeo eep eer ees eo- eoa eob eoc eod eoe eoo eop eor eos ep- epa epb epc epd epe epo epp epr eps era erb erc erd ere ero erp err ers es- esa esb esc esd ese eso esp esr ess oaa oab oac oad oae oao oap oar oas ob- oba obb obc obd obe obo obp obr obs oc- oca ocb occ ocd oco ocp ocr ocs oda odb odc odd ode odo odp odr ods oea oeb oec oed oee oeo oep oer oes oo- ooa oob ooc ood ooo oop oor oos op- opa opb opc opd ope opo opp opr ops or- ora orb orc ord ore oro orp orr ors os- osa osb osc osd ose oso osp osr oss p-p paa pab pac pad pae pao pap par pas pba pbb pbc pbd pbe pbo pbp pbr pbs pca pcb pcc pcd pce pco pcp pcr pcs pda pdb pdc pdd pde pdo pdp pdr pds pea peb pec ped pee peo pep per pes poa pob poc pod poe poo pop por pos ppa ppb ppc ppd ppe ppo ppp ppr pps pra prb prc prd pre pro prp prr prs ps- psa psb psc psd pse pso psp psr pss ra- raa rab rac rad rae rao rap rar ras rba rbb rbc rbd rbe rbo rbp rbr rbs rca rcb rcc rcd rce rco rcp rcr rcs rda rdb rdc rdd rde rdo rdp rdr rds re- rea reb rec red ree reo rep rer res roa rob roc rod roe roo rop ror ros rpa rpb rpc rpd rpe rpo rpp rpr rps rra rrb rrc rrd rrp rrr rrs rsa rsb rsc rsd rse rso rsp rsr rss saa sab sac sad sae sao sap sar sas sba sbb sbc sbd sbe sbo sbp sbr sbs sca scb scc scd sce sco scp scr scs sda sdb sdc sdd sde sdo sdp sdr sds se- sea seb sec sed see seo sep ser ses soa sob soc sod soe soo sop sor sos spa spb spc spd spe spo spp spr sps sr- sra srb src srd sre sro srp srr srs ss- ssa ssb ssc ssd sse sso ssp ssr sss