-er a-a a-b a-c a-t aaa aab aac aad aae aao aap aar aat ab- aba abb abc abd abe abo abp abr abt ac- aca acb acc acd ace aco acp acr act ad- ada adb adc add ade ado adp adr adt aea aeb aec aed aee aeo aep aer aet aoa aob aoc aod aoe aoo aop aor aot ap- apa apb apc apd ape apo app apr apt ar- ara arb arc ard are aro arp arr art at- ata atb atc atd ate ato atp atr att b-p baa bab bac bad bae bao bap bar bat bba bbb bbc bbd bbe bbo bbp bbr bbt bca bcb bcc bcd bce bco bcp bcr bct bda bdb bdc bdd bde bdo bdp bdr bdt be- bea beb bec bed bee beo bep ber bet boa bob boc bod boe boo bop bor bot bpa bpb bpc bpd bpe bpo bpp bpr bpt bra brb brd bre bro brp brr brt bta btb btc btd bte bto btp btr btt c-- caa cab cac cad cae cao cap car cat cba cbb cbc cbd cbe cbo cbp cbr cbt cca ccb ccc ccd cce cco ccp ccr cct cda cdb cdc cdd cde cdo cdp cdr cdt ce- cea ceb cec ced cee ceo cep cer cet co- coa cob coc cod coe coo cop cor cot cpa cpb cpc cpd cpe cpo cpp cpr cpt cra crb crc crd cre cro crp crr crt cta ctb ctc ctd cte cto ctp ctr ctt daa dab dac dad dae dao dap dar dat dba dbb dbc dbd dbe dbo dbp dbr dbt dca dcb dcc dcd dce dco dcp dcr dct dda ddb ddc ddd dde ddo ddp ddr ddt de- dea deb dec ded dee deo dep der det doa dob doc dod doe doo dop dor dot dpa dpb dpc dpd dpe dpo dpp dpr dpt dra drb drc drd dre dro drp drr drt dta dtb dtc dtd dte dto dtp dtr dtt eaa eab eac ead eae eao eap ear eat eba ebb ebc ebd ebe ebo ebp ebr ebt ec- eca ecb ecc ecd ece eco ecr ect ed- eda edb edc edd ede edo edp edr edt eea eeb eec eed eee eeo eep eer eet eo- eoa eob eoc eod eoe eoo eop eor eot ep- epa epb epc epd epe epo epp epr ept era erb erc erd ere ero erp err ert eta etb etc etd ete eto etp etr ett oaa oab oac oad oae oao oap oar oat ob- oba obb obc obd obe obo obp obr obt oc- oca ocb occ ocd oco ocp ocr oct oda odb odc odd ode odo odp odr odt oea oeb oec oed oee oeo oep oer oet oo- ooa oob ooc ood ooo oop oor oot op- opa opb opc opd ope opo opp opr opt or- ora orb orc ord ore oro orp orr ort ot- ota otb otc otd ote oto otp otr ott p-p paa pab pac pad pae pao pap par pat pba pbb pbc pbd pbe pbo pbp pbr pbt pca pcb pcc pcd pce pco pcp pcr pct pda pdb pdc pdd pde pdo pdp pdr pdt pea peb pec ped pee peo pep per pet poa pob poc pod poe poo pop por pot ppa ppb ppc ppd ppe ppo ppp ppr ppt pra prb prc prd pre pro prp prr prt pt- pta ptb ptc ptd pte pto ptp ptr ptt ra- raa rab rac rad rae rao rap rar rat rba rbb rbc rbd rbe rbo rbp rbr rbt rca rcb rcc rcd rce rco rcp rcr rct rda rdb rdc rdd rde rdo rdp rdr rdt re- rea reb rec red ree reo rep rer ret roa rob roc rod roe roo rop ror rot rpa rpb rpc rpd rpe rpo rpp rpr rpt rra rrb rrc rrd rrp rrr rrt rta rtb rtc rtd rte rto rtp rtr rtt taa tab tac tad tae tao tap tar tat tba tbb tbc tbd tbe tbo tbp tbr tbt tca tcb tcc tcd tce tco tcp tcr tct tda tdb tdc tdd tde tdo tdp tdr tdt te- tea teb tec ted tee teo tep ter tet to- toa tob toc tod toe too top tor tot tpa tpb tpc tpd tpe tpo tpp tpr tpt tra trb trc trd tre tro trp trr trt tta ttb ttc ttd tte tto ttp ttr ttt