a-a a-b a-c aaa aab aac aae aan aas aau ab- aba abb abc abe abn abs abu ac- aca acb acc ace acn acs acu aea aeb aec aee aen aes aeu an- ana anb anc ane ann ans anu as- asa asb asc ase asn ass asu au- aua aub auc aue aun aus b-u baa bab bac bae ban bas bau bba bbb bbc bbe bbn bbs bbu bca bcb bcc bce bcn bcs bcu be- bea beb bec bee ben bes beu bna bnb bnc bne bnn bns bnu bsa bsb bsc bse bsn bss bsu bua bub buc bue bun bus buu c-- caa cab cac cae can cas cau cba cbb cbc cbe cbn cbs cbu cca ccb ccc cce ccn ccs ccu ce- cea ceb cec cee cen ces ceu cn- cna cnb cnc cne cnn cns cnu csa csb csc cse csn css csu cua cub cuc cue cun cus cuu eaa eab eac eae ean eas eau eba ebb ebc ebe ebn ebs ebu ec- eca ecb ecc ece ecn ecs ecu eea eeb eec eee een ees en- ena enb enc ene enn ens enu es- esa esb esc ese esn ess esu eu- eua eub euc eue eun eus naa nab nac nae nan nas nau nba nbb nbc nbe nbn nbs nbu nca ncb ncc nce ncn ncs ncu ne- nea neb nec nee nen nes neu nna nnb nnc nne nnn nns nnu nsa nsb nsc nse nsn nss nsu nua nub nuc nue nun nus nuu saa sab sac sae san sas sau sba sbb sbc sbe sbn sbs sbu sca scb scc sce scn scs scu se- sea seb sec see sen ses seu sna snb snc sne snn sns snu ss- ssa ssb ssc sse ssn sss ssu sua sub suc sue sun sus suu ua- uaa uab uac uae uan uas uau uba ubb ubc ube ubn ubs ubu uca ucb ucc uce ucn ucs ucu uea ueb uec uee uen ues un- una unb unc une unn uns unu usa usb usc use usn uss usu uua uuc uue uun uus uuu