-ic a-a a-b a-c a-i aaa aab aac aai aak aan ab- aba abb abc abi abk abn ac- aca acb acc aci ack acn ai- aia aib aic aii aik ain aka akb akc aki akk akn an- ana anb anc ani ank ann baa bab bac bai bak ban bba bbb bbc bbi bbk bbn bca bcb bcc bci bck bcn bi- bia bib bic bii bik bin bka bkb bkc bkk bkn bna bnb bnc bni bnk bnn c-- caa cab cac cai cak can cba cbb cbc cbi cbk cbn cca ccb ccc cci cck ccn ci- cia cib cic cii cik cin cka ckb ckc cki cn- cna cnb cnc cni cnn ia- iaa iab iac iai ian iba ibb ibc ibi ibk ibn ica icb icc ici ick icn iia iib iic iii iin ika ikb ikc iki ikk in- ina inb inc ini ink inn ka- kaa kab kac kai kak kan kba kbb kbc kbi kbk kbn kca kcb kcc kci kck kcn kia kib kic kii kik kin kkb kkc kki kkk kkn kn- kna knc kni knk knn n-i naa nab nac nai nak nan nba nbb nbc nbi nbk nbn nca ncb ncc nci nck ncn nia nib nic nii nik nin nka nkc nki nkk nkn nna nnb nnc nni nnk nnn