-ic a-a a-b a-c a-i aaa aab aac aai aas aax ab- aba abb abc abi abs abx ac- aca acb acc aci acs acx ai- aia aib aic aii ais aix as- asa asb asc asi ass asx ax- axa axi axs axx baa bab bac bai bas bax bba bbb bbc bbi bbs bbx bca bcb bcc bci bcs bcx bi- bia bib bic bii bis bix bsa bsb bsc bsi bss bsx bxb bxi bxx c-- caa cab cac cai cas cax cba cbb cbc cbi cbs cbx cca ccb ccc cci ccs ccx ci- cia cib cic cii cis cix csa csb csc csi css csx cxc cxi cxs cxx ia- iaa iab iac iai ias iba ibb ibc ibi ibs ibx ica icb icc ici ics iia iib iic iii iis iix is- isa isb isc isi iss ixc ixi saa sab sac sai sas sax sba sbb sbc sbi sbs sbx sca scb scc sci scs scx sia sib sic sii sis six ss- ssa ssb ssc ssi sss ssx sxc sxi sxs xaa xac xas xbc xbx xcb xci xcx xia xic xii xis xix xsa xsb xsc xsi xss xxi xxx