a-a a-b a-c a-t aaa aab aac aae aao aas aat aax ab- aba abb abc abe abo abs abt abx ac- aca acb acc ace aco acs act acx aea aeb aec aee aeo aes aet aex aoa aob aoc aoe aoo aos aot aox as- asa asb asc ase aso ass ast asx at- ata atb atc ate ato ats att atx ax- axa axe axo axs axt axx baa bab bac bae bao bas bat bax bba bbb bbc bbe bbo bbs bbt bbx bca bcb bcc bce bco bcs bct bcx be- bea beb bec bee beo bes bet bex boa bob boc boe boo bos bot box bsa bsb bsc bse bso bss bst bsx bta btb btc bte bto bts btt btx bxb bxo bxx c-- caa cab cac cae cao cas cat cax cba cbb cbc cbe cbo cbs cbt cbx cca ccb ccc cce cco ccs cct ccx ce- cea ceb cec cee ceo ces cet cex co- coa cob coc coe coo cos cot cox csa csb csc cse cso css cst csx cta ctb ctc cte cto cts ctt ctx cxc cxo cxs cxt cxx eaa eab eac eae eao eas eat eax eba ebb ebc ebe ebo ebs ebt ebx ec- eca ecb ecc ece eco ecs ect ecx eea eeb eec eee eeo ees eet eex eo- eoa eob eoc eoe eoo eos eot es- esa esb esc ese eso ess est esx eta etb etc ete eto ets ett etx ex- exa exc exe exo exs ext exx oaa oab oac oae oao oas oat oax ob- oba obb obc obe obo obs obt obx oc- oca ocb occ oco ocs oct ocx oea oeb oec oee oeo oes oet oex oo- ooa oob ooc ooo oos oot oox os- osa osb osc ose oso oss ost osx ot- ota otb otc ote oto ots ott ox- oxa oxb oxc oxo oxt oxx saa sab sac sae sao sas sat sax sba sbb sbc sbe sbo sbs sbt sbx sca scb scc sce sco scs sct scx se- sea seb sec see seo ses set sex soa sob soc soe soo sos sot sox ss- ssa ssb ssc sse sso sss sst ssx sta stb stc ste sto sts stt stx sxc sxs sxt t-x taa tab tac tae tao tas tat tax tba tbb tbc tbe tbo tbs tbt tca tcb tcc tce tco tcs tct tcx te- tea teb tec tee teo tes tet tex to- toa tob toc toe too tos tot tox tsa tsb tsc tse tso tss tst tsx tta ttb ttc tte tto tts ttt ttx txe txs txt xaa xac xas xat xbc xbe xbx xcb xcx xee xes xet xex xoa xoc xoo xos xot xox xsa xsb xsc xss xst xtc xts xtx xxo xxx