-er a-a a-b a-c aaa aab aac aad aae aar aau ab- aba abb abc abd abe abr abu ac- aca acb acc acd ace acr acu ad- ada adb adc add ade adr adu aea aeb aec aed aee aer aeu ar- ara arb arc ard are arr aru au- aua aub auc aud aue aur b-u baa bab bac bad bae bar bau bba bbb bbc bbd bbe bbr bbu bca bcb bcc bcd bce bcr bcu bda bdb bdc bdd bde bdr bdu be- bea beb bec bed bee ber beu bra brb brd bre brr bru bua bub buc bud bue bur buu c-- caa cab cac cad cae car cau cba cbb cbc cbd cbe cbr cbu cca ccb ccc ccd cce ccr ccu cda cdb cdc cdd cde cdr cdu ce- cea ceb cec ced cee cer ceu cra crb crc crd cre crr cru cua cub cuc cud cue cur cuu daa dab dac dad dae dar dau dba dbb dbc dbd dbe dbr dbu dca dcb dcc dcd dce dcr dcu dda ddb ddc ddd dde ddr ddu de- dea deb dec ded dee der deu dra drb drc drd dre drr dru dua dub duc dud due dur eaa eab eac ead eae ear eau eba ebb ebc ebd ebe ebr ebu ec- eca ecb ecc ecd ece ecr ecu ed- eda edb edc edd ede edr edu eea eeb eec eed eee eer era erb erc erd ere err eru eu- eua eub euc eud eue eur ra- raa rab rac rad rae rar rau rba rbb rbc rbd rbe rbr rbu rca rcb rcc rcd rce rcr rcu rda rdb rdc rdd rde rdr rdu re- rea reb rec red ree rer reu rra rrb rrc rrd rrr rru rua rub ruc rud rue rur ruu ua- uaa uab uac uad uae uar uau uba ubb ubc ube ubr ubu uca ucb ucc ucd uce ucr ucu uda udb udc udd ude udr udu uea ueb uec ued uee uer ur- ura urb urc urd ure urr uru uua uuc uue uur uuu