a-a a-b a-c aaa aab aac aag aar aas aau ab- aba abb abc abg abr abs abu ac- aca acb acc acg acr acs acu ag- aga agb agc agg agr ags agu ar- ara arb arc arg arr ars aru as- asa asb asc asg asr ass asu au- aua aub auc aug aur aus b-u baa bab bac bag bar bas bau bba bbb bbc bbg bbr bbs bbu bca bcb bcc bcg bcr bcs bcu bga bgb bgc bgg bgr bgs bgu bra brb brg brr brs bru bsa bsb bsc bsg bsr bss bsu bua bub buc bug bur bus buu c-- caa cab cac cag car cas cau cba cbb cbc cbg cbr cbs cbu cca ccb ccc ccg ccr ccs ccu cga cgb cgc cgg cgr cgs cgu cra crb crc crg crr crs cru csa csb csc csg csr css csu cua cub cuc cug cur cus cuu gaa gab gac gag gar gas gau gba gbc gbg gbr gbs gbu gca gcb gcc gcg gcr gcs gcu gga ggb ggc ggg ggr ggs ggu gra grb grc grg grr grs gru gsa gsb gsc gsg gsr gss gsu gu- gua gub guc gug gur gus guu ra- raa rab rac rag rar ras rau rba rbb rbc rbg rbr rbs rbu rca rcb rcc rcg rcr rcs rcu rga rgb rgc rgg rgr rgs rra rrb rrc rrg rrr rrs rru rsa rsb rsc rsg rsr rss rsu rua rub ruc rug rur rus ruu saa sab sac sag sar sas sau sba sbb sbc sbg sbr sbs sbu sca scb scc scg scr scs scu sga sgb sgc sgg sgr sgs sgu sr- sra srb src srg srr srs ss- ssa ssb ssc ssg ssr sss ssu sua sub suc sug sur sus suu ua- uaa uab uac uag uar uas uau uba ubb ubc ubg ubr ubs ubu uca ucb ucc ucg ucr ucs ucu uga ugb ugc ugg ugr ugs ugu ur- ura urb urc urg urr urs uru usa usb usc usg usr uss usu uua uuc uug uur uus uuu