-er a-a a-b a-c a-t aaa aab aac aae aar aas aat aau ab- aba abb abc abe abr abs abt abu ac- aca acb acc ace acr acs act acu aea aeb aec aee aer aes aet aeu ar- ara arb arc are arr ars art aru as- asa asb asc ase asr ass ast asu at- ata atb atc ate atr ats att atu au- aua aub auc aue aur aus aut b-u baa bab bac bae bar bas bat bau bba bbb bbc bbe bbr bbs bbt bbu bca bcb bcc bce bcr bcs bct bcu be- bea beb bec bee ber bes bet beu bra brb bre brr brs brt bru bsa bsb bsc bse bsr bss bst bsu bta btb btc bte btr bts btt btu bua bub buc bue bur bus but buu c-- caa cab cac cae car cas cat cau cba cbb cbc cbe cbr cbs cbt cbu cca ccb ccc cce ccr ccs cct ccu ce- cea ceb cec cee cer ces cet ceu cra crb crc cre crr crs crt cru csa csb csc cse csr css cst csu cta ctb ctc cte ctr cts ctt ctu cua cub cuc cue cur cus cut cuu eaa eab eac eae ear eas eat eau eba ebb ebc ebe ebr ebs ebt ebu ec- eca ecb ecc ece ecr ecs ect ecu eea eeb eec eee eer ees eet era erb erc ere err ers ert eru es- esa esb esc ese esr ess est esu eta etb etc ete etr ets ett etu eu- eua eub euc eue eur eus eut ra- raa rab rac rae rar ras rat rau rba rbb rbc rbe rbr rbs rbt rbu rca rcb rcc rce rcr rcs rct rcu re- rea reb rec ree rer res ret reu rra rrb rrc rrr rrs rrt rru rsa rsb rsc rse rsr rss rst rsu rta rtb rtc rte rtr rts rtt rtu rua rub ruc rue rur rus rut ruu saa sab sac sae sar sas sat sau sba sbb sbc sbe sbr sbs sbt sbu sca scb scc sce scr scs sct scu se- sea seb sec see ser ses set seu sr- sra srb src sre srr srs srt ss- ssa ssb ssc sse ssr sss sst ssu sta stb stc ste str sts stt stu sua sub suc sue sur sus sut suu taa tab tac tae tar tas tat tau tba tbb tbc tbe tbr tbs tbt tbu tca tcb tcc tce tcr tcs tct tcu te- tea teb tec tee ter tes tet teu tra trb trc tre trr trs trt tru tsa tsb tsc tse tsr tss tst tsu tta ttb ttc tte ttr tts ttt ttu tua tub tuc tue tur tus tut tuu ua- uaa uab uac uae uar uas uat uau uba ubb ubc ube ubr ubs ubt ubu uca ucb ucc uce ucr ucs uct ucu uea ueb uec uee uer ues uet ur- ura urb urc ure urr urs urt uru usa usb usc use usr uss ust usu uta utb utc ute utr uts utt utu uua uuc uue uur uus uut uuu