-er a-a a-b a-c a-t aaa aab aac aae aar aat aau ab- aba abb abc abe abr abt abu ac- aca acb acc ace acr act acu aea aeb aec aee aer aet aeu ar- ara arb arc are arr art aru at- ata atb atc ate atr att atu au- aua aub auc aue aur aut b-u baa bab bac bae bar bat bau bba bbb bbc bbe bbr bbt bbu bca bcb bcc bce bcr bct bcu be- bea beb bec bee ber bet beu bra brb bre brr brt bru bta btb btc bte btr btt btu bua bub buc bue bur but buu c-- caa cab cac cae car cat cau cba cbb cbc cbe cbr cbt cbu cca ccb ccc cce ccr cct ccu ce- cea ceb cec cee cer cet ceu cra crb crc cre crr crt cru cta ctb ctc cte ctr ctt ctu cua cub cuc cue cur cut cuu eaa eab eac eae ear eat eau eba ebb ebc ebe ebr ebt ebu ec- eca ecb ecc ece ecr ect ecu eea eeb eec eee eer eet era erb erc ere err ert eru eta etb etc ete etr ett etu eu- eua eub euc eue eur eut ra- raa rab rac rae rar rat rau rba rbb rbc rbe rbr rbt rbu rca rcb rcc rce rcr rct rcu re- rea reb rec ree rer ret reu rra rrb rrc rrr rrt rru rta rtb rtc rte rtr rtt rtu rua rub ruc rue rur rut ruu taa tab tac tae tar tat tau tba tbb tbc tbe tbr tbt tbu tca tcb tcc tce tcr tct tcu te- tea teb tec tee ter tet teu tra trb trc tre trr trt tru tta ttb ttc tte ttr ttt ttu tua tub tuc tue tur tut tuu ua- uaa uab uac uae uar uat uau uba ubb ubc ube ubr ubt ubu uca ucb ucc uce ucr uct ucu uea ueb uec uee uer uet ur- ura urb urc ure urr urt uru uta utb utc ute utr utt utu uua uuc uue uur uut uuu