-ic a-a a-b a-c a-i aaa aab aac aai aao aas aay ab- aba abb abc abi abo abs aby ac- aca acb acc aci aco acs acy ai- aia aib aic aii aio ais aiy aoa aob aoc aoi aoo aos as- asa asb asc asi aso ass asy ay- aya ayc ayi ayo ays baa bab bac bai bao bas bay bba bbb bbc bbi bbo bbs bby bca bcb bcc bci bco bcs bcy bi- bia bib bic bii bio bis biy boa bob boc boi boo bos boy bsa bsb bsc bsi bso bss bsy by- bya byc byi byo bys c-- caa cab cac cai cao cas cay cba cbb cbc cbi cbo cbs cby cca ccb ccc cci cco ccs ci- cia cib cic cii cio cis co- coa cob coc coi coo cos coy csa csb csc csi cso css csy cya cyb cyc cyo cys ia- iaa iab iac iai iao ias iba ibb ibc ibi ibo ibs iby ica icb icc ici ico ics icy iia iib iic iii iio iis io- ioa iob ioc ioi ioo ios is- isa isb isc isi iso iss isy iya iyc iyo iys iyy o-i oaa oab oac oai oao oas ob- oba obb obc obi obo obs oby oc- oca ocb occ oci oco ocs oia oib oic oii oio ois oo- ooa oob ooc ooi ooo oos os- osa osb osc osi oso oss oya oyi oyo oys saa sab sac sai sao sas say sba sbb sbc sbi sbo sbs sby sca scb scc sci sco scs sia sib sic sii sio sis soa sob soc soi soo sos soy ss- ssa ssb ssc ssi sso sss sy- sya syb syc syi sys yaa yab yac yai yao yas yay ybc ybi ybs yby yca ycc yci yco ycs ycy yii yio yis yob yoc yoi yoo yos yoy ysa ysb ysc ysi yso yss ysy yyb yyc yys yyy