-ic a-a a-b a-c a-i a-t aaa aab aac aai aas aat aax ab- aba abb abc abi abs abt abx ac- aca acb acc aci acs act acx ai- aia aib aic aii ais ait aix as- asa asb asc asi ass ast asx at- ata atb atc ati ats att atx ax- axa axi axs axt axx baa bab bac bai bas bat bax bba bbb bbc bbi bbs bbt bbx bca bcb bcc bci bcs bct bcx bi- bia bib bic bii bis bit bix bsa bsb bsc bsi bss bst bsx bta btb btc bti bts btt btx bxb bxi bxx c-- caa cab cac cai cas cat cax cba cbb cbc cbi cbs cbt cbx cca ccb ccc cci ccs cct ccx ci- cia cib cic cii cis cit cix csa csb csc csi css cst csx cta ctb ctc cti cts ctt ctx cxc cxi cxs cxt cxx ia- iaa iab iac iai ias iat iba ibb ibc ibi ibs ibt ibx ica icb icc ici ics ict iia iib iic iii iis iit iix is- isa isb isc isi iss ist ita itb itc iti its itt itx ixc ixi saa sab sac sai sas sat sax sba sbb sbc sbi sbs sbt sbx sca scb scc sci scs sct scx sia sib sic sii sis sit six ss- ssa ssb ssc ssi sss sst ssx sta stb stc sti sts stt stx sxc sxi sxs sxt t-x taa tab tac tai tas tat tax tba tbb tbc tbi tbs tbt tca tcb tcc tci tcs tct tcx tia tib tic tii tis tit tix tsa tsb tsc tsi tss tst tsx tta ttb ttc tti tts ttt ttx txi txs txt xaa xac xas xat xbc xbx xcb xci xcx xia xic xii xis xit xix xsa xsb xsc xsi xss xst xtc xti xts xtx xxi xxx