-ic a-a a-b a-c a-i aaa aab aac aai aak aan aas ab- aba abb abc abi abk abn abs ac- aca acb acc aci ack acn acs ai- aia aib aic aii aik ain ais aka akb akc aki akk akn aks an- ana anb anc ani ank ann ans as- asa asb asc asi ask asn ass baa bab bac bai bak ban bas bba bbb bbc bbi bbk bbn bbs bca bcb bcc bci bck bcn bcs bi- bia bib bic bii bik bin bis bka bkb bkc bkk bkn bks bna bnb bnc bni bnk bnn bns bsa bsb bsc bsi bsk bsn bss c-- caa cab cac cai cak can cas cba cbb cbc cbi cbk cbn cbs cca ccb ccc cci cck ccn ccs ci- cia cib cic cii cik cin cis cka ckb ckc cki cks cn- cna cnb cnc cni cnn cns csa csb csc csi csk csn css ia- iaa iab iac iai ian ias iba ibb ibc ibi ibk ibn ibs ica icb icc ici ick icn ics iia iib iic iii iin iis ika ikb ikc iki ikk iks in- ina inb inc ini ink inn ins is- isa isb isc isi isk isn iss ka- kaa kab kac kai kak kan kas kba kbb kbc kbi kbk kbn kbs kca kcb kcc kci kck kcn kcs kia kib kic kii kik kin kis kkb kkc kki kkk kkn kks kn- kna knc kni knk knn ksa ksb ksc ksi ksk ksn kss n-i naa nab nac nai nak nan nas nba nbb nbc nbi nbk nbn nbs nca ncb ncc nci nck ncn ncs nia nib nic nii nik nin nis nka nkc nki nkk nkn nks nna nnb nnc nni nnk nnn nns nsa nsb nsc nsi nsk nsn nss saa sab sac sai sak san sas sba sbb sbc sbi sbk sbn sbs sca scb scc sci sck scn scs sia sib sic sii sik sin sis sk- ska skb skc ski skk sks sna snb snc sni snk snn sns ss- ssa ssb ssc ssi ssk ssn sss