a-a a-b a-c a-t aaa aab aac aaf aao aar aas aat aau ab- aba abb abc abf abo abr abs abt abu ac- aca acb acc acf aco acr acs act acu af- afa afb afc aff afo afr afs aft afu aoa aob aoc aof aoo aor aos aot aou ar- ara arb arc arf aro arr ars art aru as- asa asb asc asf aso asr ass ast asu at- ata atb atc atf ato atr ats att atu au- aua aub auc auf auo aur aus aut b-u baa bab bac baf bao bar bas bat bau bba bbb bbc bbf bbo bbr bbs bbt bbu bca bcb bcc bcf bco bcr bcs bct bcu bfa bfb bfc bff bfo bfr bfs bft bfu boa bob boc bof boo bor bos bot bou bra brb brf bro brr brs brt bru bsa bsb bsc bsf bso bsr bss bst bsu bta btb btc btf bto btr bts btt btu bua bub buc buf buo bur bus but buu c-- caa cab cac caf cao car cas cat cau cba cbb cbc cbf cbo cbr cbs cbt cbu cca ccb ccc ccf cco ccr ccs cct ccu cfa cfb cfc cff cfo cfr cfs cft cfu co- coa cob coc cof coo cor cos cot cou cra crb crc crf cro crr crs crt cru csa csb csc csf cso csr css cst csu cta ctb ctc ctf cto ctr cts ctt ctu cua cub cuc cuf cuo cur cus cut cuu faa fab fac faf fao far fas fat fau fba fbb fbc fbf fbo fbr fbs fbt fbu fca fcb fcc fcf fco fcr fcs fct fcu ffa ffc fff ffo ffr ffs fft ffu foa fob foc fof foo for fos fot fou fra frb frc frf fro frr frs frt fru fsa fsb fsc fsf fso fsr fss fst fsu fta ftb ftc ftf fto ftr fts ftt ftu fua fub fuf fuo fur fus fut fuu oaa oab oac oaf oao oar oas oat oau ob- oba obb obc obf obo obr obs obt obu oc- oca ocb occ ocf oco ocr ocs oct ocu of- ofa ofb ofc off ofo ofr ofs oft ofu oo- ooa oob ooc oof ooo oor oos oot or- ora orb orc orf oro orr ors ort oru os- osa osb osc osf oso osr oss ost osu ot- ota otb otc otf oto otr ots ott otu ou- oua ouc ouf ouo our ous out ra- raa rab rac raf rao rar ras rat rau rba rbb rbc rbf rbo rbr rbs rbt rbu rca rcb rcc rcf rco rcr rcs rct rcu rfa rfb rfc rff rfo rfr rfs rft rfu roa rob roc rof roo ror ros rot rou rra rrb rrc rrf rrr rrs rrt rru rsa rsb rsc rsf rso rsr rss rst rsu rta rtb rtc rtf rto rtr rts rtt rtu rua rub ruc ruf ruo rur rus rut ruu saa sab sac saf sao sar sas sat sau sba sbb sbc sbf sbo sbr sbs sbt sbu sca scb scc scf sco scr scs sct scu sfa sfb sfc sff sfo sfr sfs sft sfu soa sob soc sof soo sor sos sot sou sr- sra srb src srf sro srr srs srt ss- ssa ssb ssc ssf sso ssr sss sst ssu sta stb stc stf sto str sts stt stu sua sub suc suf suo sur sus sut suu taa tab tac taf tao tar tas tat tau tba tbb tbc tbf tbo tbr tbs tbt tbu tca tcb tcc tcf tco tcr tcs tct tcu tfa tfb tfc tff tfo tfr tfs tft tfu to- toa tob toc tof too tor tos tot tou tra trb trc trf tro trr trs trt tru tsa tsb tsc tsf tso tsr tss tst tsu tta ttb ttc ttf tto ttr tts ttt ttu tua tub tuc tuf tuo tur tus tut tuu ua- uaa uab uac uaf uao uar uas uat uau uba ubb ubc ubf ubo ubr ubs ubt ubu uca ucb ucc ucf uco ucr ucs uct ucu ufa ufc uff ufo ufr ufs uft ufu uoa uob uoc uoo uor uos uot ur- ura urb urc urf uro urr urs urt uru usa usb usc usf uso usr uss ust usu uta utb utc utf uto utr uts utt utu uua uuc uur uus uut uuu