a-a a-b a-c aaa aab aac aaf aan aas aau ab- aba abb abc abf abn abs abu ac- aca acb acc acf acn acs acu af- afa afb afc aff afn afs afu an- ana anb anc anf ann ans anu as- asa asb asc asf asn ass asu au- aua aub auc auf aun aus b-u baa bab bac baf ban bas bau bba bbb bbc bbf bbn bbs bbu bca bcb bcc bcf bcn bcs bcu bfa bfb bfc bff bfn bfs bfu bna bnb bnc bnf bnn bns bnu bsa bsb bsc bsf bsn bss bsu bua bub buc buf bun bus buu c-- caa cab cac caf can cas cau cba cbb cbc cbf cbn cbs cbu cca ccb ccc ccf ccn ccs ccu cfa cfb cfc cff cfn cfs cfu cn- cna cnb cnc cnf cnn cns cnu csa csb csc csf csn css csu cua cub cuc cuf cun cus cuu faa fab fac faf fan fas fau fba fbb fbc fbf fbn fbs fbu fca fcb fcc fcf fcn fcs fcu ffa ffc fff ffn ffs ffu fna fnb fnc fnf fnn fns fnu fsa fsb fsc fsf fsn fss fsu fua fub fuf fun fus fuu naa nab nac naf nan nas nau nba nbb nbc nbf nbn nbs nbu nca ncb ncc ncf ncn ncs ncu nfa nfb nfc nff nfn nfs nfu nna nnb nnc nnf nnn nns nnu nsa nsb nsc nsf nsn nss nsu nua nub nuc nun nus nuu saa sab sac saf san sas sau sba sbb sbc sbf sbn sbs sbu sca scb scc scf scn scs scu sfa sfb sfc sff sfn sfs sfu sna snb snc snf snn sns snu ss- ssa ssb ssc ssf ssn sss ssu sua sub suc suf sun sus suu ua- uaa uab uac uaf uan uas uau uba ubb ubc ubf ubn ubs ubu uca ucb ucc ucf ucn ucs ucu ufa ufc uff ufn ufs ufu un- una unb unc unf unn uns unu usa usb usc usf usn uss usu uua uuc uun uus uuu