-er a-a a-b a-c aaa aab aac aae aaf aah aao aar aas ab- aba abb abc abe abf abh abo abr abs ac- aca acb acc ace acf ach aco acr acs aea aeb aec aee aef aeh aeo aer aes af- afa afb afc afe aff afh afo afr afs aha ahb ahc ahe ahf ahh aho ahr ahs aoa aob aoc aoe aof aoh aoo aor aos ar- ara arb arc are arf arh aro arr ars as- asa asb asc ase asf ash aso asr ass baa bab bac bae baf bah bao bar bas bba bbb bbc bbe bbf bbh bbo bbr bbs bca bcb bcc bce bcf bch bco bcr bcs be- bea beb bec bee bef beh beo ber bes bfa bfb bfc bfe bff bfh bfo bfr bfs bha bhb bhc bhe bhf bhh bho bhr bhs boa bob boc boe bof boh boo bor bos bra brb bre brf brh bro brr brs bsa bsb bsc bse bsf bsh bso bsr bss c-- caa cab cac cae caf cah cao car cas cba cbb cbc cbe cbf cbh cbo cbr cbs cca ccb ccc cce ccf cch cco ccr ccs ce- cea ceb cec cee cef ceh ceo cer ces cfa cfb cfc cfe cff cfh cfo cfr cfs ch- cha chb chc che chf chh cho chr chs co- coa cob coc coe cof coh coo cor cos cra crb crc cre crf crh cro crr crs csa csb csc cse csf csh cso csr css eaa eab eac eae eaf eah eao ear eas eba ebb ebc ebe ebf ebh ebo ebr ebs ec- eca ecb ecc ece ecf ech eco ecr ecs eea eeb eec eee eef eeo eer ees ef- efa efb efc efe eff efh efo efr efs eha ehb ehc ehe ehf ehh eho ehr ehs eo- eoa eob eoc eoe eof eoh eoo eor eos era erb erc ere erf erh ero err ers es- esa esb esc ese esf esh eso esr ess faa fab fac fae faf fah fao far fas fba fbb fbc fbe fbf fbh fbo fbr fbs fca fcb fcc fce fcf fco fcr fcs fea feb fec fee fef feh feo fer fes ffa ffc ffe fff ffh ffo ffr ffs fha fhb fhc fhe fhf fhh fho fhr fhs foa fob foc foe fof foh foo for fos fra frb frc fre frf frh fro frr frs fsa fsb fsc fse fsf fsh fso fsr fss haa hab hac hae haf hah hao har has hba hbb hbc hbe hbf hbh hbo hbr hbs hca hcb hcc hce hcf hch hco hcr hcs he- hea heb hec hee hef heh heo her hes hfa hfb hfc hfe hff hfh hfo hfr hfs hha hhb hhc hhe hhf hhh hho hhr hhs hoa hob hoc hoe hof hoh hoo hor hos hr- hra hrb hrc hre hrf hrh hro hrr hrs hsa hsb hsc hse hsf hsh hsr hss oaa oab oac oae oaf oah oao oar oas ob- oba obb obc obe obf obh obo obr obs oc- oca ocb occ ocf och oco ocr ocs oea oeb oec oee oef oeh oeo oer oes of- ofa ofb ofc ofe off ofo ofr ofs oha ohc ohe ohf ohh oho ohr ohs oo- ooa oob ooc oof ooh ooo oor oos or- ora orb orc ore orf orh oro orr ors os- osa osb osc ose osf osh oso osr oss ra- raa rab rac rae raf rah rao rar ras rba rbb rbc rbe rbf rbh rbo rbr rbs rca rcb rcc rce rcf rch rco rcr rcs re- rea reb rec ree ref reh reo rer res rfa rfb rfc rfe rff rfh rfo rfr rfs rh- rha rhb rhc rhe rhf rhh rho rhr rhs roa rob roc roe rof roh roo ror ros rra rrb rrc rrf rrh rrr rrs rsa rsb rsc rse rsf rsh rso rsr rss saa sab sac sae saf sah sao sar sas sba sbb sbc sbe sbf sbh sbo sbr sbs sca scb scc sce scf sch sco scr scs se- sea seb sec see sef seh seo ser ses sfa sfb sfc sfe sff sfh sfo sfr sfs sh- sha shb shc she shf shh sho shr shs soa sob soc soe sof soh soo sor sos sr- sra srb src sre srf srh sro srr srs ss- ssa ssb ssc sse ssf ssh sso ssr sss