-ic a-a a-b a-c a-i aaa aab aac aai aak ab- aba abb abc abi abk ac- aca acb acc aci ack ai- aia aib aic aii aik aka akb akc aki akk baa bab bac bai bak bba bbb bbc bbi bbk bca bcb bcc bci bck bi- bia bib bic bii bik bka bkb bkc bkk c-- caa cab cac cai cak cba cbb cbc cbi cbk cca ccb ccc cci cck ci- cia cib cic cii cik cka ckb ckc cki ia- iaa iab iac iai iba ibb ibc ibi ibk ica icb icc ici ick iia iib iic iii ika ikb ikc iki ikk ka- kaa kab kac kai kak kba kbb kbc kbi kbk kca kcb kcc kci kck kia kib kic kii kik kkb kkc kki kkk