-ic a-a a-b a-c a-i aaa aab aac aaf aai aak aan aas ab- aba abb abc abf abi abk abn abs ac- aca acb acc acf aci ack acn acs af- afa afb afc aff afi afk afn afs ai- aia aib aic aif aii aik ain ais aka akb akc aki akk akn aks an- ana anb anc anf ani ank ann ans as- asa asb asc asf asi ask asn ass baa bab bac baf bai bak ban bas bba bbb bbc bbf bbi bbk bbn bbs bca bcb bcc bcf bci bck bcn bcs bfa bfb bfc bff bfi bfn bfs bi- bia bib bic bif bii bik bin bis bka bkb bkc bkf bkk bkn bks bna bnb bnc bnf bni bnk bnn bns bsa bsb bsc bsf bsi bsk bsn bss c-- caa cab cac caf cai cak can cas cba cbb cbc cbf cbi cbk cbn cbs cca ccb ccc ccf cci cck ccn ccs cfa cfb cfc cff cfi cfk cfn cfs ci- cia cib cic cif cii cik cin cis cka ckb ckc cki cks cn- cna cnb cnc cnf cni cnn cns csa csb csc csf csi csk csn css faa fab fac faf fai fak fan fas fba fbb fbc fbf fbi fbk fbn fbs fca fcb fcc fcf fci fck fcn fcs ffa ffc fff ffi ffk ffn ffs fia fib fic fif fii fik fin fis fka fkb fkc fkf fki fkk fna fnb fnc fnf fni fnk fnn fns fsa fsb fsc fsf fsi fsk fsn fss i-f ia- iaa iab iac iaf iai ian ias iba ibb ibc ibf ibi ibk ibn ibs ica icb icc icf ici ick icn ics ifa ifb ifc iff ifi ifn ifs iia iib iic iif iii iin iis ika ikb ikc ikf iki ikk iks in- ina inb inc inf ini ink inn ins is- isa isb isc isf isi isk isn iss ka- kaa kab kac kaf kai kak kan kas kba kbb kbc kbf kbi kbk kbn kbs kca kcb kcc kci kck kcn kcs kfa kfc kff kfi kfs kia kib kic kif kii kik kin kis kkb kkc kki kkk kkn kks kn- kna knc knf kni knk knn ksa ksb ksc ksf ksi ksk ksn kss n-i naa nab nac naf nai nak nan nas nba nbb nbc nbf nbi nbk nbn nbs nca ncb ncc ncf nci nck ncn ncs nfa nfb nfc nff nfi nfk nfn nfs nia nib nic nif nii nik nin nis nka nkc nkf nki nkk nkn nks nna nnb nnc nnf nni nnk nnn nns nsa nsb nsc nsf nsi nsk nsn nss saa sab sac saf sai sak san sas sba sbb sbc sbf sbi sbk sbn sbs sca scb scc scf sci sck scn scs sfa sfb sfc sff sfi sfk sfn sfs sia sib sic sif sii sik sin sis sk- ska skb skc skf ski skk sks sna snb snc snf sni snk snn sns ss- ssa ssb ssc ssf ssi ssk ssn sss