a-a a-b a-c a-z aaa aab aac aag aas aau aaz ab- aba abb abc abg abs abu abz ac- aca acb acc acg acs acu acz ag- aga agb agc agg ags agu agz as- asa asb asc asg ass asu asz au- aua aub auc aug aus auz az- aza azb azg azs azu azz b-u baa bab bac bag bas bau baz bba bbb bbc bbg bbs bbu bca bcb bcc bcg bcs bcu bcz bga bgb bgc bgg bgs bgu bgz bsa bsb bsc bsg bss bsu bua bub buc bug bus buu buz bza bzs bzu bzz c-- caa cab cac cag cas cau caz cba cbb cbc cbg cbs cbu cbz cca ccb ccc ccg ccs ccu ccz cga cgb cgc cgg cgs cgu csa csb csc csg css csu csz cua cub cuc cug cus cuu cuz cz- czc gaa gab gac gag gas gau gaz gba gbc gbg gbs gbu gbz gca gcb gcc gcg gcs gcu gga ggb ggc ggg ggs ggu ggz gsa gsb gsc gsg gss gsu gu- gua gub guc gug gus guu guz gza gzu saa sab sac sag sas sau saz sba sbb sbc sbg sbs sbu sca scb scc scg scs scu sga sgb sgc sgg sgs sgu ss- ssa ssb ssc ssg sss ssu ssz sua sub suc sug sus suu suz sza szu ua- uaa uab uac uag uas uau uaz uba ubb ubc ubg ubs ubu uca ucb ucc ucg ucs ucu uga ugb ugc ugg ugs ugu usa usb usc usg uss usu usz uua uuc uug uus uuu uza uzb uzu z-g zaa zab zac zag zas zaz zbb zbc zbs zcs zgb zgg zgs zsa zsg zsu zsz zub zuc zug zus zuz zzs zzz