a-a a-b a-c aaa aab aac aae aao aas aau aax ab- aba abb abc abe abo abs abu abx ac- aca acb acc ace aco acs acu acx aea aeb aec aee aeo aes aeu aex aoa aob aoc aoe aoo aos aou aox as- asa asb asc ase aso ass asu asx au- aua aub auc aue auo aus aux ax- axa axe axo axs axx b-u baa bab bac bae bao bas bau bax bba bbb bbc bbe bbo bbs bbu bbx bca bcb bcc bce bco bcs bcu bcx be- bea beb bec bee beo bes beu bex boa bob boc boe boo bos bou box bsa bsb bsc bse bso bss bsu bsx bua bub buc bue buo bus buu bux bxb bxo bxx c-- caa cab cac cae cao cas cau cax cba cbb cbc cbe cbo cbs cbu cbx cca ccb ccc cce cco ccs ccu ccx ce- cea ceb cec cee ceo ces ceu cex co- coa cob coc coe coo cos cou cox csa csb csc cse cso css csu csx cua cub cuc cue cuo cus cuu cxc cxo cxs cxx eaa eab eac eae eao eas eau eax eba ebb ebc ebe ebo ebs ebu ebx ec- eca ecb ecc ece eco ecs ecu ecx eea eeb eec eee eeo ees eex eo- eoa eob eoc eoe eoo eos eou es- esa esb esc ese eso ess esu esx eu- eua eub euc eue eus eux ex- exa exc exe exo exs exu exx oaa oab oac oae oao oas oau oax ob- oba obb obc obe obo obs obu obx oc- oca ocb occ oco ocs ocu ocx oea oeb oec oee oeo oes oex oo- ooa oob ooc ooo oos oox os- osa osb osc ose oso oss osu osx ou- oua ouc oue ouo ous ox- oxa oxb oxc oxo oxx saa sab sac sae sao sas sau sax sba sbb sbc sbe sbo sbs sbu sbx sca scb scc sce sco scs scu scx se- sea seb sec see seo ses seu sex soa sob soc soe soo sos sou sox ss- ssa ssb ssc sse sso sss ssu ssx sua sub suc sue suo sus suu sux sxc sxs sxu ua- uaa uab uac uae uao uas uau uba ubb ubc ube ubo ubs ubu ubx uca ucb ucc uce uco ucs ucu uea ueb uec uee ues uoa uob uoc uoe uoo uos uox usa usb usc use uso uss usu usx uua uuc uue uus uuu uxb uxc uxo uxu xaa xac xas xau xbc xbe xbx xcb xcx xee xes xeu xex xoa xoc xoo xos xox xsa xsb xsc xss xue xus xxo xxx