a-a a-b a-c aaa aab aac aae aah aak aas ab- aba abb abc abe abh abk abs ac- aca acb acc ace ach ack acs aea aeb aec aee aeh aek aes aha ahb ahc ahe ahh ahk ahs aka akb akc ake akh akk aks as- asa asb asc ase ash ask ass baa bab bac bae bah bak bas bba bbb bbc bbe bbh bbk bbs bca bcb bcc bce bch bck bcs be- bea beb bec bee beh bek bes bha bhb bhc bhe bhh bhk bhs bka bkb bkc bke bkk bks bsa bsb bsc bse bsh bsk bss c-- caa cab cac cae cah cak cas cba cbb cbc cbe cbh cbk cbs cca ccb ccc cce cch cck ccs ce- cea ceb cec cee ceh cek ces ch- cha chb chc che chh chk chs cka ckb ckc ckh cks csa csb csc cse csh csk css eaa eab eac eae eah eak eas eba ebb ebc ebe ebh ebk ebs ec- eca ecb ecc ece ech eck ecs eea eeb eec eee eek ees eha ehb ehc ehe ehh ehs eka ekb ekc eke ekh eks es- esa esb esc ese esh esk ess haa hab hac hae hah hak has hba hbb hbc hbe hbh hbk hbs hca hcb hcc hce hch hck hcs he- hea heb hec hee heh hek hes hha hhb hhc hhe hhh hhk hhs hka hkb hkh hkk hks hsa hsb hsc hse hsh hsk hss ka- kaa kab kac kae kah kak kas kba kbb kbc kbe kbh kbk kbs kca kcb kcc kce kch kck kcs ke- kea keb kec kee keh kek kes kha khe khh khk khs kkb kkc kke kkh kkk kks ksa ksb ksc kse ksh ksk kss saa sab sac sae sah sak sas sba sbb sbc sbe sbh sbk sbs sca scb scc sce sch sck scs se- sea seb sec see seh sek ses sh- sha shb shc she shh shk shs sk- ska skb skc ske skh skk sks ss- ssa ssb ssc sse ssh ssk sss