-er a-a a-b a-c aaa aab aac aad aae aao aar aau ab- aba abb abc abd abe abo abr abu ac- aca acb acc acd ace aco acr acu ad- ada adb adc add ade ado adr adu aea aeb aec aed aee aeo aer aeu aoa aob aoc aod aoe aoo aor aou ar- ara arb arc ard are aro arr aru au- aua aub auc aud aue auo aur b-u baa bab bac bad bae bao bar bau bba bbb bbc bbd bbe bbo bbr bbu bca bcb bcc bcd bce bco bcr bcu bda bdb bdc bdd bde bdo bdr bdu be- bea beb bec bed bee beo ber beu boa bob boc bod boe boo bor bou bra brb brd bre bro brr bru bua bub buc bud bue buo bur buu c-- caa cab cac cad cae cao car cau cba cbb cbc cbd cbe cbo cbr cbu cca ccb ccc ccd cce cco ccr ccu cda cdb cdc cdd cde cdo cdr cdu ce- cea ceb cec ced cee ceo cer ceu co- coa cob coc cod coe coo cor cou cra crb crc crd cre cro crr cru cua cub cuc cud cue cuo cur cuu daa dab dac dad dae dao dar dau dba dbb dbc dbd dbe dbo dbr dbu dca dcb dcc dcd dce dco dcr dcu dda ddb ddc ddd dde ddo ddr ddu de- dea deb dec ded dee deo der deu doa dob doc dod doe doo dor dou dra drb drc drd dre dro drr dru dua dub duc dud due duo dur eaa eab eac ead eae eao ear eau eba ebb ebc ebd ebe ebo ebr ebu ec- eca ecb ecc ecd ece eco ecr ecu ed- eda edb edc edd ede edo edr edu eea eeb eec eed eee eeo eer eo- eoa eob eoc eod eoe eoo eor eou era erb erc erd ere ero err eru eu- eua eub euc eud eue eur oaa oab oac oad oae oao oar oau ob- oba obb obc obd obe obo obr obu oc- oca ocb occ ocd oco ocr ocu oda odb odc odd ode odo odr odu oea oeb oec oed oee oeo oer oo- ooa oob ooc ood ooo oor or- ora orb orc ord ore oro orr oru ou- oua ouc oud oue ouo our ra- raa rab rac rad rae rao rar rau rba rbb rbc rbd rbe rbo rbr rbu rca rcb rcc rcd rce rco rcr rcu rda rdb rdc rdd rde rdo rdr rdu re- rea reb rec red ree reo rer reu roa rob roc rod roe roo ror rou rra rrb rrc rrd rrr rru rua rub ruc rud rue ruo rur ruu ua- uaa uab uac uad uae uao uar uau uba ubb ubc ube ubo ubr ubu uca ucb ucc ucd uce uco ucr ucu uda udb udc udd ude udo udr udu uea ueb uec ued uee uer uoa uob uoc uod uoe uoo uor ur- ura urb urc urd ure uro urr uru uua uuc uue uur uuu