-er a-a a-b a-c aaa aab aac aae aaf aah aar aas ab- aba abb abc abe abf abh abr abs ac- aca acb acc ace acf ach acr acs aea aeb aec aee aef aeh aer aes af- afa afb afc afe aff afh afr afs aha ahb ahc ahe ahf ahh ahr ahs ar- ara arb arc are arf arh arr ars as- asa asb asc ase asf ash asr ass baa bab bac bae baf bah bar bas bba bbb bbc bbe bbf bbh bbr bbs bca bcb bcc bce bcf bch bcr bcs be- bea beb bec bee bef beh ber bes bfa bfb bfc bfe bff bfh bfr bfs bha bhb bhc bhe bhf bhh bhr bhs bra brb bre brf brh brr brs bsa bsb bsc bse bsf bsh bsr bss c-- caa cab cac cae caf cah car cas cba cbb cbc cbe cbf cbh cbr cbs cca ccb ccc cce ccf cch ccr ccs ce- cea ceb cec cee cef ceh cer ces cfa cfb cfc cfe cff cfh cfr cfs ch- cha chb chc che chf chh chr chs cra crb crc cre crf crh crr crs csa csb csc cse csf csh csr css eaa eab eac eae eaf eah ear eas eba ebb ebc ebe ebf ebh ebr ebs ec- eca ecb ecc ece ecf ech ecr ecs eea eeb eec eee eef eer ees ef- efa efb efc efe eff efh efr efs eha ehb ehc ehe ehf ehh ehr ehs era erb erc ere erf erh err ers es- esa esb esc ese esf esh esr ess faa fab fac fae faf fah far fas fba fbb fbc fbe fbf fbh fbr fbs fca fcb fcc fce fcf fcr fcs fea feb fec fee fef feh fer fes ffa ffc ffe fff ffh ffr ffs fha fhb fhc fhe fhf fhh fhr fhs fra frb frc fre frf frh frr frs fsa fsb fsc fse fsf fsh fsr fss haa hab hac hae haf hah har has hba hbb hbc hbe hbf hbh hbr hbs hca hcb hcc hce hcf hch hcr hcs he- hea heb hec hee hef heh her hes hfa hfb hfc hfe hff hfh hfr hfs hha hhb hhc hhe hhf hhh hhr hhs hr- hra hrb hrc hre hrf hrh hrr hrs hsa hsb hsc hse hsf hsh hsr hss ra- raa rab rac rae raf rah rar ras rba rbb rbc rbe rbf rbh rbr rbs rca rcb rcc rce rcf rch rcr rcs re- rea reb rec ree ref reh rer res rfa rfb rfc rfe rff rfh rfr rfs rh- rha rhb rhc rhe rhf rhh rhr rhs rra rrb rrc rrf rrh rrr rrs rsa rsb rsc rse rsf rsh rsr rss saa sab sac sae saf sah sar sas sba sbb sbc sbe sbf sbh sbr sbs sca scb scc sce scf sch scr scs se- sea seb sec see sef seh ser ses sfa sfb sfc sfe sff sfh sfr sfs sh- sha shb shc she shf shh shr shs sr- sra srb src sre srf srh srr srs ss- ssa ssb ssc sse ssf ssh ssr sss