-ic a-a a-b a-c a-i aaa aab aac aai aak aan aax ab- aba abb abc abi abk abn abx ac- aca acb acc aci ack acn acx ai- aia aib aic aii aik ain aix aka akb akc aki akk akn an- ana anb anc ani ank ann anx ax- axa axi axk axn axx baa bab bac bai bak ban bax bba bbb bbc bbi bbk bbn bbx bca bcb bcc bci bck bcn bcx bi- bia bib bic bii bik bin bix bka bkb bkc bkk bkn bkx bna bnb bnc bni bnk bnn bnx bxb bxi bxn bxx c-- caa cab cac cai cak can cax cba cbb cbc cbi cbk cbn cbx cca ccb ccc cci cck ccn ccx ci- cia cib cic cii cik cin cix cka ckb ckc cki ckx cn- cna cnb cnc cni cnn cnx cxc cxi cxk cxx ia- iaa iab iac iai ian iba ibb ibc ibi ibk ibn ibx ica icb icc ici ick icn iia iib iic iii iin iix ika ikb ikc iki ikk ikx in- ina inb inc ini ink inn inx ixc ixi ixn ka- kaa kab kac kai kak kan kax kba kbb kbc kbi kbk kbn kbx kca kcb kcc kci kck kcn kcx kia kib kic kii kik kin kix kkb kkc kki kkk kkn kn- kna knc kni knk knn knx n-i naa nab nac nai nak nan nax nba nbb nbc nbi nbk nbn nbx nca ncb ncc nci nck ncn ncx nia nib nic nii nik nin nix nka nkc nki nkk nkn nna nnb nnc nni nnk nnn nxc xaa xac xak xan xbc xbx xcb xci xcx xia xic xii xin xix xkb xna xnc xnk xxi xxx