-er a-a a-b a-c a-t aaa aab aac aad aae aan aao aar aat ab- aba abb abc abd abe abn abo abr abt ac- aca acb acc acd ace acn aco acr act ad- ada adb adc add ade adn ado adr adt aea aeb aec aed aee aen aeo aer aet an- ana anb anc and ane ann ano anr ant aoa aob aoc aod aoe aon aoo aor aot ar- ara arb arc ard are arn aro arr art at- ata atb atc atd ate atn ato atr att baa bab bac bad bae ban bao bar bat bba bbb bbc bbd bbe bbn bbo bbr bbt bca bcb bcc bcd bce bcn bco bcr bct bda bdb bdc bdd bde bdo bdr bdt be- bea beb bec bed bee ben beo ber bet bna bnb bnc bnd bne bnn bno bnr bnt boa bob boc bod boe bon boo bor bot bra brb brd bre brn bro brr brt bta btb btc btd bte btn bto btr btt c-- caa cab cac cad cae can cao car cat cba cbb cbc cbd cbe cbn cbo cbr cbt cca ccb ccc ccd cce ccn cco ccr cct cda cdb cdc cdd cde cdn cdo cdr cdt ce- cea ceb cec ced cee cen ceo cer cet cn- cna cnb cnc cnd cne cnn cno cnr cnt co- coa cob coc cod coe con coo cor cot cra crb crc crd cre crn cro crr crt cta ctb ctc ctd cte ctn cto ctr ctt daa dab dac dad dae dan dao dar dat dba dbb dbc dbd dbe dbn dbo dbr dbt dca dcb dcc dcd dce dcn dco dcr dct dda ddb ddc ddd dde ddn ddo ddr ddt de- dea deb dec ded dee den deo der det dna dnb dnc dnd dne dnn dno dnr dnt doa dob doc dod doe don doo dor dot dra drb drc drd dre drn dro drr drt dta dtb dtc dtd dte dtn dto dtr dtt eaa eab eac ead eae ean eao ear eat eba ebb ebc ebd ebe ebn ebo ebr ebt ec- eca ecb ecc ecd ece ecn eco ecr ect ed- eda edb edc edd ede edn edo edr edt eea eeb eec eed eee een eeo eer eet en- ena enb enc end ene enn eno enr ent eo- eoa eob eoc eod eoe eon eoo eor eot era erb erc erd ere ern ero err ert eta etb etc etd ete etn eto etr ett naa nab nac nad nae nan nao nar nat nba nbb nbc nbd nbe nbn nbo nbr nbt nca ncb ncc ncd nce ncn nco ncr nct nda ndb ndc ndd nde ndn ndo ndr ndt ne- nea neb nec ned nee nen neo ner net nna nnb nnc nne nnn nno nnt no- noa nob noc nod noe non noo nor not nra nrb nrc nrd nre nrn nro nrr nrt nta ntb ntc ntd nte ntn nto ntr ntt oaa oab oac oad oae oan oao oar oat ob- oba obb obc obd obe obn obo obr obt oc- oca ocb occ ocd ocn oco ocr oct oda odb odc odd ode odn odo odr odt oea oeb oec oed oee oen oeo oer oet on- ona onb onc ond one onn ono onr ont oo- ooa oob ooc ood oon ooo oor oot or- ora orb orc ord ore orn oro orr ort ot- ota otb otc otd ote otn oto otr ott ra- raa rab rac rad rae ran rao rar rat rba rbb rbc rbd rbe rbn rbo rbr rbt rca rcb rcc rcd rce rcn rco rcr rct rda rdb rdc rdd rde rdn rdo rdr rdt re- rea reb rec red ree ren reo rer ret rna rnb rnc rnd rnn rno rnr rnt roa rob roc rod roe ron roo ror rot rra rrb rrc rrd rrn rrr rrt rta rtb rtc rtd rte rtn rto rtr rtt taa tab tac tad tae tan tao tar tat tba tbb tbc tbd tbe tbn tbo tbr tbt tca tcb tcc tcd tce tcn tco tcr tct tda tdb tdc tdd tde tdn tdo tdr tdt te- tea teb tec ted tee ten teo ter tet tna tnb tnc tnd tne tnn tno tnr tnt to- toa tob toc tod toe ton too tor tot tra trb trc trd tre trn tro trr trt tta ttb ttc ttd tte ttn tto ttr ttt