a-a a-b a-c aaa aab aac aag aao aar aau ab- aba abb abc abg abo abr abu ac- aca acb acc acg aco acr acu ag- aga agb agc agg ago agr agu aoa aob aoc aog aoo aor aou ar- ara arb arc arg aro arr aru au- aua aub auc aug auo aur b-u baa bab bac bag bao bar bau bba bbb bbc bbg bbo bbr bbu bca bcb bcc bcg bco bcr bcu bga bgb bgc bgg bgo bgr bgu boa bob boc bog boo bor bou bra brb brg bro brr bru bua bub buc bug buo bur buu c-- caa cab cac cag cao car cau cba cbb cbc cbg cbo cbr cbu cca ccb ccc ccg cco ccr ccu cga cgb cgc cgg cgo cgr cgu co- coa cob coc cog coo cor cou cra crb crc crg cro crr cru cua cub cuc cug cuo cur cuu gaa gab gac gag gao gar gau gba gbc gbg gbo gbr gbu gca gcb gcc gcg gco gcr gcu gga ggb ggc ggg ggo ggr ggu goa gob goc gog goo gor gou gra grb grc grg gro grr gru gu- gua gub guc gug guo gur guu oaa oab oac oag oao oar oau ob- oba obb obc obg obo obr obu oc- oca ocb occ ocg oco ocr ocu oga ogc ogg ogo oo- ooa oob ooc oog ooo oor or- ora orb orc org oro orr oru ou- oua ouc ouo our ra- raa rab rac rag rao rar rau rba rbb rbc rbg rbo rbr rbu rca rcb rcc rcg rco rcr rcu rga rgb rgc rgg rgo rgr roa rob roc rog roo ror rou rra rrb rrc rrg rrr rru rua rub ruc rug ruo rur ruu ua- uaa uab uac uag uao uar uau uba ubb ubc ubg ubo ubr ubu uca ucb ucc ucg uco ucr ucu uga ugb ugc ugg ugo ugr ugu uoa uob uoc uog uoo uor ur- ura urb urc urg uro urr uru uua uuc uug uur uuu