a-a a-b a-c aaa aab aac aao aas aau aav ab- aba abb abc abo abs abu abv ac- aca acb acc aco acs acu acv aoa aob aoc aoo aos aou aov as- asa asb asc aso ass asu asv au- aua aub auc auo aus auv av- ava avb avc avo avs avu b-u baa bab bac bao bas bau bav bba bbb bbc bbo bbs bbu bca bcb bcc bco bcs bcu bcv boa bob boc boo bos bou bov bsa bsb bsc bso bss bsu bsv bua bub buc buo bus buu bva bvb bvc bvo bvs bvu bvv c-- caa cab cac cao cas cau cav cba cbb cbc cbo cbs cbu cbv cca ccb ccc cco ccs ccu ccv co- coa cob coc coo cos cou cov csa csb csc cso css csu csv cua cub cuc cuo cus cuu cuv cva cvb cvc cvo cvs cvu cvv oaa oab oac oao oas oau oav ob- oba obb obc obo obs obu obv oc- oca ocb occ oco ocs ocu ocv oo- ooa oob ooc ooo oos oov os- osa osb osc oso oss osu osv ou- oua ouc ouo ous ov- ova ovb ovc ovo ovs ovv saa sab sac sao sas sau sav sba sbb sbc sbo sbs sbu sbv sca scb scc sco scs scu scv soa sob soc soo sos sou sov ss- ssa ssb ssc sso sss ssu ssv sua sub suc suo sus suu suv sva svb svc svo svs svu svv ua- uaa uab uac uao uas uau uav uba ubb ubc ubo ubs ubu ubv uca ucb ucc uco ucs ucu ucv uoa uob uoc uoo uos usa usb usc uso uss usu usv uua uuc uus uuu uva uvb uvc uvo uvs uvu uvv v-a vaa vab vac vao vas vau vav vba vbc vbo vbs vbv vca vcc vco vcs vcu voa vob voc voo vos vou vov vsa vsb vsc vso vss vsu vsv vus vuv vva vvb vvc vvo vvs vvv