a-a a-b a-c a-t aaa aab aac aae aas aat ab- aba abb abc abe abs abt ac- aca acb acc ace acs act aea aeb aec aee aes aet as- asa asb asc ase ass ast at- ata atb atc ate ats att baa bab bac bae bas bat bba bbb bbc bbe bbs bbt bca bcb bcc bce bcs bct be- bea beb bec bee bes bet bsa bsb bsc bse bss bst bta btb btc bte bts btt c-- caa cab cac cae cas cat cba cbb cbc cbe cbs cbt cca ccb ccc cce ccs cct ce- cea ceb cec cee ces cet csa csb csc cse css cst cta ctb ctc cte cts ctt eaa eab eac eae eas eat eba ebb ebc ebe ebs ebt ec- eca ecb ecc ece ecs ect eea eeb eec eee ees eet es- esa esb esc ese ess est eta etb etc ete ets ett saa sab sac sae sas sat sba sbb sbc sbe sbs sbt sca scb scc sce scs sct se- sea seb sec see ses set ss- ssa ssb ssc sse sss sst sta stb stc ste sts stt taa tab tac tae tas tat tba tbb tbc tbe tbs tbt tca tcb tcc tce tcs tct te- tea teb tec tee tes tet tsa tsb tsc tse tss tst tta ttb ttc tte tts ttt