-ic a-a a-b a-c a-i aaa aab aac aai aak aay ab- aba abb abc abi abk aby ac- aca acb acc aci ack acy ai- aia aib aic aii aik aiy aka akb akc aki akk ay- aya ayc ayi ayk baa bab bac bai bak bay bba bbb bbc bbi bbk bby bca bcb bcc bci bck bcy bi- bia bib bic bii bik biy bka bkb bkc bkk by- bya byc byi byk c-- caa cab cac cai cak cay cba cbb cbc cbi cbk cby cca ccb ccc cci cck ci- cia cib cic cii cik cka ckb ckc cki cky cya cyb cyc cyk ia- iaa iab iac iai iba ibb ibc ibi ibk iby ica icb icc ici ick icy iia iib iic iii ika ikb ikc iki ikk iya iyc iyy ka- kaa kab kac kai kak kay kba kbb kbc kbi kbk kca kcb kcc kci kck kia kib kic kii kik kkb kkc kki kkk kky kya kyc yaa yab yac yai yak yay ybc ybi yby yca ycc yci ycy yii yka yki ykk yyb yyc yyy