a-a a-b aaa aab aae aaf aah aas ab- aba abb abe abf abh abs aea aeb aee aef aeh aes af- afa afb afe aff afh afs aha ahb ahe ahf ahh ahs as- asa asb ase asf ash ass baa bab bae baf bah bas bba bbb bbe bbf bbh bbs be- bea beb bee bef beh bes bfa bfb bfe bff bfh bfs bha bhb bhe bhf bhh bhs bsa bsb bse bsf bsh bss eaa eab eae eaf eah eas eba ebb ebe ebf ebh ebs eea eeb eee eef ees ef- efa efb efe eff efh efs eha ehb ehe ehf ehh ehs es- esa esb ese esf esh ess faa fab fae faf fah fas fba fbb fbe fbf fbh fbs fea feb fee fef feh fes ffa ffe fff ffh ffs fha fhb fhe fhf fhh fhs fsa fsb fse fsf fsh fss haa hab hae haf hah has hba hbb hbe hbf hbh hbs he- hea heb hee hef heh hes hfa hfb hfe hff hfh hfs hha hhb hhe hhf hhh hhs hsa hsb hse hsf hsh hss saa sab sae saf sah sas sba sbb sbe sbf sbh sbs se- sea seb see sef seh ses sfa sfb sfe sff sfh sfs sh- sha shb she shf shh shs ss- ssa ssb sse ssf ssh sss