a-a a-b a-c aaa aab aac aad aas aau ab- aba abb abc abd abs abu ac- aca acb acc acd acs acu ad- ada adb adc add ads adu as- asa asb asc asd ass asu au- aua aub auc aud aus b-u baa bab bac bad bas bau bba bbb bbc bbd bbs bbu bca bcb bcc bcd bcs bcu bda bdb bdc bdd bds bdu bsa bsb bsc bsd bss bsu bua bub buc bud bus buu c-- caa cab cac cad cas cau cba cbb cbc cbd cbs cbu cca ccb ccc ccd ccs ccu cda cdb cdc cdd cds cdu csa csb csc csd css csu cua cub cuc cud cus cuu daa dab dac dad das dau dba dbb dbc dbd dbs dbu dca dcb dcc dcd dcs dcu dda ddb ddc ddd dds ddu dsa dsb dsc dsd dss dsu dua dub duc dud dus saa sab sac sad sas sau sba sbb sbc sbd sbs sbu sca scb scc scd scs scu sda sdb sdc sdd sds sdu ss- ssa ssb ssc ssd sss ssu sua sub suc sud sus suu ua- uaa uab uac uad uas uau uba ubb ubc ubs ubu uca ucb ucc ucd ucs ucu uda udb udc udd uds udu usa usb usc usd uss usu uua uuc uus uuu