-er a-a a-b a-c a-t aaa aab aac aae aao aar aat aau ab- aba abb abc abe abo abr abt abu ac- aca acb acc ace aco acr act acu aea aeb aec aee aeo aer aet aeu aoa aob aoc aoe aoo aor aot aou ar- ara arb arc are aro arr art aru at- ata atb atc ate ato atr att atu au- aua aub auc aue auo aur aut b-u baa bab bac bae bao bar bat bau bba bbb bbc bbe bbo bbr bbt bbu bca bcb bcc bce bco bcr bct bcu be- bea beb bec bee beo ber bet beu boa bob boc boe boo bor bot bou bra brb bre bro brr brt bru bta btb btc bte bto btr btt btu bua bub buc bue buo bur but buu c-- caa cab cac cae cao car cat cau cba cbb cbc cbe cbo cbr cbt cbu cca ccb ccc cce cco ccr cct ccu ce- cea ceb cec cee ceo cer cet ceu co- coa cob coc coe coo cor cot cou cra crb crc cre cro crr crt cru cta ctb ctc cte cto ctr ctt ctu cua cub cuc cue cuo cur cut cuu eaa eab eac eae eao ear eat eau eba ebb ebc ebe ebo ebr ebt ebu ec- eca ecb ecc ece eco ecr ect ecu eea eeb eec eee eeo eer eet eo- eoa eob eoc eoe eoo eor eot eou era erb erc ere ero err ert eru eta etb etc ete eto etr ett etu eu- eua eub euc eue eur eut oaa oab oac oae oao oar oat oau ob- oba obb obc obe obo obr obt obu oc- oca ocb occ oco ocr oct ocu oea oeb oec oee oeo oer oet oo- ooa oob ooc ooo oor oot or- ora orb orc ore oro orr ort oru ot- ota otb otc ote oto otr ott otu ou- oua ouc oue ouo our out ra- raa rab rac rae rao rar rat rau rba rbb rbc rbe rbo rbr rbt rbu rca rcb rcc rce rco rcr rct rcu re- rea reb rec ree reo rer ret reu roa rob roc roe roo ror rot rou rra rrb rrc rrr rrt rru rta rtb rtc rte rto rtr rtt rtu rua rub ruc rue ruo rur rut ruu taa tab tac tae tao tar tat tau tba tbb tbc tbe tbo tbr tbt tbu tca tcb tcc tce tco tcr tct tcu te- tea teb tec tee teo ter tet teu to- toa tob toc toe too tor tot tou tra trb trc tre tro trr trt tru tta ttb ttc tte tto ttr ttt ttu tua tub tuc tue tuo tur tut tuu ua- uaa uab uac uae uao uar uat uau uba ubb ubc ube ubo ubr ubt ubu uca ucb ucc uce uco ucr uct ucu uea ueb uec uee uer uet uoa uob uoc uoe uoo uor uot ur- ura urb urc ure uro urr urt uru uta utb utc ute uto utr utt utu uua uuc uue uur uut uuu