a-a a-b a-c a-t aaa aab aac aae aak aas aat ab- aba abb abc abe abk abs abt ac- aca acb acc ace ack acs act aea aeb aec aee aek aes aet aka akb akc ake akk aks as- asa asb asc ase ask ass ast at- ata atb atc ate ats att baa bab bac bae bak bas bat bba bbb bbc bbe bbk bbs bbt bca bcb bcc bce bck bcs bct be- bea beb bec bee bek bes bet bka bkb bkc bke bkk bks bkt bsa bsb bsc bse bsk bss bst bta btb btc bte btk bts btt c-- caa cab cac cae cak cas cat cba cbb cbc cbe cbk cbs cbt cca ccb ccc cce cck ccs cct ce- cea ceb cec cee cek ces cet cka ckb ckc cks ckt csa csb csc cse csk css cst cta ctb ctc cte ctk cts ctt eaa eab eac eae eak eas eat eba ebb ebc ebe ebk ebs ebt ec- eca ecb ecc ece eck ecs ect eea eeb eec eee eek ees eet eka ekb ekc eke eks ekt es- esa esb esc ese esk ess est eta etb etc ete etk ets ett k-t ka- kaa kab kac kae kak kas kat kba kbb kbc kbe kbk kbs kca kcb kcc kce kck kcs kct ke- kea keb kec kee kek kes ket kkb kkc kke kkk kks kkt ksa ksb ksc kse ksk kss kst kta ktb ktc kte ktk kts ktt saa sab sac sae sak sas sat sba sbb sbc sbe sbk sbs sbt sca scb scc sce sck scs sct se- sea seb sec see sek ses set sk- ska skb skc ske skk sks skt ss- ssa ssb ssc sse ssk sss sst sta stb stc ste stk sts stt taa tab tac tae tak tas tat tba tbb tbc tbe tbk tbs tbt tca tcb tcc tce tck tcs tct te- tea teb tec tee tek tes tet tka tkb tkc tke tkk tks tkt tsa tsb tsc tse tsk tss tst tta ttb ttc tte ttk tts ttt