-ic a-a a-b a-c a-i aaa aab aac aai aak aas aay ab- aba abb abc abi abk abs aby ac- aca acb acc aci ack acs acy ai- aia aib aic aii aik ais aiy aka akb akc aki akk aks as- asa asb asc asi ask ass asy ay- aya ayc ayi ayk ays baa bab bac bai bak bas bay bba bbb bbc bbi bbk bbs bby bca bcb bcc bci bck bcs bcy bi- bia bib bic bii bik bis biy bka bkb bkc bkk bks bsa bsb bsc bsi bsk bss bsy by- bya byc byi byk bys c-- caa cab cac cai cak cas cay cba cbb cbc cbi cbk cbs cby cca ccb ccc cci cck ccs ci- cia cib cic cii cik cis cka ckb ckc cki cks cky csa csb csc csi csk css csy cya cyb cyc cyk cys ia- iaa iab iac iai ias iba ibb ibc ibi ibk ibs iby ica icb icc ici ick ics icy iia iib iic iii iis ika ikb ikc iki ikk iks is- isa isb isc isi isk iss isy iya iyc iys iyy ka- kaa kab kac kai kak kas kay kba kbb kbc kbi kbk kbs kca kcb kcc kci kck kcs kia kib kic kii kik kis kkb kkc kki kkk kks kky ksa ksb ksc ksi ksk kss kya kyc kys saa sab sac sai sak sas say sba sbb sbc sbi sbk sbs sby sca scb scc sci sck scs sia sib sic sii sik sis sk- ska skb skc ski skk sks sky ss- ssa ssb ssc ssi ssk sss sy- sya syb syc syi syk sys yaa yab yac yai yak yas yay ybc ybi ybs yby yca ycc yci ycs ycy yii yis yka yki ykk ysa ysb ysc ysi ysk yss ysy yyb yyc yys yyy