-ic a-a a-b a-c a-i aaa aab aac aai aas aay ab- aba abb abc abi abs aby ac- aca acb acc aci acs acy ai- aia aib aic aii ais aiy as- asa asb asc asi ass asy ay- aya ayc ayi ays baa bab bac bai bas bay bba bbb bbc bbi bbs bby bca bcb bcc bci bcs bcy bi- bia bib bic bii bis biy bsa bsb bsc bsi bss bsy by- bya byc byi bys c-- caa cab cac cai cas cay cba cbb cbc cbi cbs cby cca ccb ccc cci ccs ci- cia cib cic cii cis csa csb csc csi css csy cya cyb cyc cys ia- iaa iab iac iai ias iba ibb ibc ibi ibs iby ica icb icc ici ics icy iia iib iic iii iis is- isa isb isc isi iss isy iya iyc iys iyy saa sab sac sai sas say sba sbb sbc sbi sbs sby sca scb scc sci scs sia sib sic sii sis ss- ssa ssb ssc ssi sss sy- sya syb syc syi sys yaa yab yac yai yas yay ybc ybi ybs yby yca ycc yci ycs ycy yii yis ysa ysb ysc ysi yss ysy yyb yyc yys yyy