-er a-a a-b a-c a-t aaa aab aac aae aao aar aas aat aau ab- aba abb abc abe abo abr abs abt abu ac- aca acb acc ace aco acr acs act acu aea aeb aec aee aeo aer aes aet aeu aoa aob aoc aoe aoo aor aos aot aou ar- ara arb arc are aro arr ars art aru as- asa asb asc ase aso asr ass ast asu at- ata atb atc ate ato atr ats att atu au- aua aub auc aue auo aur aus aut b-u baa bab bac bae bao bar bas bat bau bba bbb bbc bbe bbo bbr bbs bbt bbu bca bcb bcc bce bco bcr bcs bct bcu be- bea beb bec bee beo ber bes bet beu boa bob boc boe boo bor bos bot bou bra brb bre bro brr brs brt bru bsa bsb bsc bse bso bsr bss bst bsu bta btb btc bte bto btr bts btt btu bua bub buc bue buo bur bus but buu c-- caa cab cac cae cao car cas cat cau cba cbb cbc cbe cbo cbr cbs cbt cbu cca ccb ccc cce cco ccr ccs cct ccu ce- cea ceb cec cee ceo cer ces cet ceu co- coa cob coc coe coo cor cos cot cou cra crb crc cre cro crr crs crt cru csa csb csc cse cso csr css cst csu cta ctb ctc cte cto ctr cts ctt ctu cua cub cuc cue cuo cur cus cut cuu eaa eab eac eae eao ear eas eat eau eba ebb ebc ebe ebo ebr ebs ebt ebu ec- eca ecb ecc ece eco ecr ecs ect ecu eea eeb eec eee eeo eer ees eet eo- eoa eob eoc eoe eoo eor eos eot eou era erb erc ere ero err ers ert eru es- esa esb esc ese eso esr ess est esu eta etb etc ete eto etr ets ett etu eu- eua eub euc eue eur eus eut oaa oab oac oae oao oar oas oat oau ob- oba obb obc obe obo obr obs obt obu oc- oca ocb occ oco ocr ocs oct ocu oea oeb oec oee oeo oer oes oet oo- ooa oob ooc ooo oor oos oot or- ora orb orc ore oro orr ors ort oru os- osa osb osc ose oso osr oss ost osu ot- ota otb otc ote oto otr ots ott otu ou- oua ouc oue ouo our ous out ra- raa rab rac rae rao rar ras rat rau rba rbb rbc rbe rbo rbr rbs rbt rbu rca rcb rcc rce rco rcr rcs rct rcu re- rea reb rec ree reo rer res ret reu roa rob roc roe roo ror ros rot rou rra rrb rrc rrr rrs rrt rru rsa rsb rsc rse rso rsr rss rst rsu rta rtb rtc rte rto rtr rts rtt rtu rua rub ruc rue ruo rur rus rut ruu saa sab sac sae sao sar sas sat sau sba sbb sbc sbe sbo sbr sbs sbt sbu sca scb scc sce sco scr scs sct scu se- sea seb sec see seo ser ses set seu soa sob soc soe soo sor sos sot sou sr- sra srb src sre sro srr srs srt ss- ssa ssb ssc sse sso ssr sss sst ssu sta stb stc ste sto str sts stt stu sua sub suc sue suo sur sus sut suu taa tab tac tae tao tar tas tat tau tba tbb tbc tbe tbo tbr tbs tbt tbu tca tcb tcc tce tco tcr tcs tct tcu te- tea teb tec tee teo ter tes tet teu to- toa tob toc toe too tor tos tot tou tra trb trc tre tro trr trs trt tru tsa tsb tsc tse tso tsr tss tst tsu tta ttb ttc tte tto ttr tts ttt ttu tua tub tuc tue tuo tur tus tut tuu ua- uaa uab uac uae uao uar uas uat uau uba ubb ubc ube ubo ubr ubs ubt ubu uca ucb ucc uce uco ucr ucs uct ucu uea ueb uec uee uer ues uet uoa uob uoc uoe uoo uor uos uot ur- ura urb urc ure uro urr urs urt uru usa usb usc use uso usr uss ust usu uta utb utc ute uto utr uts utt utu uua uuc uue uur uus uut uuu