-ic a-a a-b a-c a-i aaa aab aac aai aan aas ab- aba abb abc abi abn abs ac- aca acb acc aci acn acs ai- aia aib aic aii ain ais an- ana anb anc ani ann ans as- asa asb asc asi asn ass baa bab bac bai ban bas bba bbb bbc bbi bbn bbs bca bcb bcc bci bcn bcs bi- bia bib bic bii bin bis bna bnb bnc bni bnn bns bsa bsb bsc bsi bsn bss c-- caa cab cac cai can cas cba cbb cbc cbi cbn cbs cca ccb ccc cci ccn ccs ci- cia cib cic cii cin cis cn- cna cnb cnc cni cnn cns csa csb csc csi csn css ia- iaa iab iac iai ian ias iba ibb ibc ibi ibn ibs ica icb icc ici icn ics iia iib iic iii iin iis in- ina inb inc ini inn ins is- isa isb isc isi isn iss n-i naa nab nac nai nan nas nba nbb nbc nbi nbn nbs nca ncb ncc nci ncn ncs nia nib nic nii nin nis nna nnb nnc nni nnn nns nsa nsb nsc nsi nsn nss saa sab sac sai san sas sba sbb sbc sbi sbn sbs sca scb scc sci scn scs sia sib sic sii sin sis sna snb snc sni snn sns ss- ssa ssb ssc ssi ssn sss