-ic a-a a-b a-c a-i a-t aaa aab aac aai aas aat aax aay ab- aba abb abc abi abs abt abx aby ac- aca acb acc aci acs act acx acy ai- aia aib aic aii ais ait aix aiy as- asa asb asc asi ass ast asx asy at- ata atb atc ati ats att atx ax- axa axi axs axt axx ay- aya ayc ayi ays ayt ayx baa bab bac bai bas bat bax bay bba bbb bbc bbi bbs bbt bbx bby bca bcb bcc bci bcs bct bcx bcy bi- bia bib bic bii bis bit bix biy bsa bsb bsc bsi bss bst bsx bsy bta btb btc bti bts btt btx bty bxb bxi bxx by- bya byc byi bys byt c-- caa cab cac cai cas cat cax cay cba cbb cbc cbi cbs cbt cbx cby cca ccb ccc cci ccs cct ccx ci- cia cib cic cii cis cit cix csa csb csc csi css cst csx csy cta ctb ctc cti cts ctt ctx cty cxc cxi cxs cxt cxx cya cyb cyc cys cyt ia- iaa iab iac iai ias iat iba ibb ibc ibi ibs ibt ibx iby ica icb icc ici ics ict icy iia iib iic iii iis iit iix is- isa isb isc isi iss ist isy ita itb itc iti its itt itx ity ixc ixi ixy iya iyc iys iyt iyy saa sab sac sai sas sat sax say sba sbb sbc sbi sbs sbt sbx sby 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 sty sxc sxi sxs sxt sy- sya syb syc syi sys syt syx t-x taa tab tac tai tas tat tax tay tba tbb tbc tbi tbs tbt tca tcb tcc tci tcs tct tcx tia tib tic tii tis tit tix tiy tsa tsb tsc tsi tss tst tsx tsy tta ttb ttc tti tts ttt ttx tty txi txs txt tya tyc tys tyt 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 xty xxi xxx xxy xyy yaa yab yac yai yas yat yax yay ybc ybi ybs yby yca ycc yci ycs ycy yii yis yit ysa ysb ysc ysi yss yst ysy yta ytc yts ytt yxa yxy yyb yyc yys yyt yyy