a-a a-b aaa aab aae aah aao aas ab- aba abb abe abh abo abs aea aeb aee aeh aeo aes aha ahb ahe ahh aho ahs aoa aob aoe aoh aoo aos as- asa asb ase ash aso ass baa bab bae bah bao bas bba bbb bbe bbh bbo bbs be- bea beb bee beh beo bes bha bhb bhe bhh bho bhs boa bob boe boh boo bos bsa bsb bse bsh bso bss eaa eab eae eah eao eas eba ebb ebe ebh ebo ebs eea eeb eee eeo ees eha ehb ehe ehh eho ehs eo- eoa eob eoe eoh eoo eos es- esa esb ese esh eso ess haa hab hae hah hao has hba hbb hbe hbh hbo hbs he- hea heb hee heh heo hes hha hhb hhe hhh hho hhs hoa hob hoe hoh hoo hos hsa hsb hse hsh hss oaa oab oae oah oao oas ob- oba obb obe obh obo obs oea oeb oee oeh oeo oes oha ohe ohh oho ohs oo- ooa oob ooh ooo oos os- osa osb ose osh oso oss saa sab sae sah sao sas sba sbb sbe sbh sbo sbs se- sea seb see seh seo ses sh- sha shb she shh sho shs soa sob soe soh soo sos ss- ssa ssb sse ssh sso sss