-er a-a a-b aaa aab aae aag aao aar aau ab- aba abb abe abg abo abr abu aea aeb aee aeg aeo aer aeu ag- aga agb age agg ago agr agu aoa aob aoe aog aoo aor aou ar- ara arb are arg aro arr aru au- aua aub aue aug auo aur b-u baa bab bae bag bao bar bau bba bbb bbe bbg bbo bbr bbu be- bea beb bee beg beo ber beu bga bgb bge bgg bgo bgr bgu boa bob boe bog boo bor bou bra brb bre brg bro brr bru bua bub bue bug buo bur buu eaa eab eae eag eao ear eau eba ebb ebe ebg ebo ebr ebu eea eeb eee eeg eeo eer ega egb ege egg ego egr egu eo- eoa eob eoe eog eoo eor eou era erb ere erg ero err eru eu- eua eub eue eug eur gaa gab gae gag gao gar gau gba gbe gbg gbo gbr gbu ge- gea geb gee geg geo ger geu gga ggb ggg ggo ggr ggu goa gob goe gog goo gor gou gra grb gre grg gro grr gru gu- gua gub gue gug guo gur guu oaa oab oae oag oao oar oau ob- oba obb obe obg obo obr obu oea oeb oee oeg oeo oer oga oge ogg ogo oo- ooa oob oog ooo oor or- ora orb ore org oro orr oru ou- oua oue ouo our ra- raa rab rae rag rao rar rau rba rbb rbe rbg rbo rbr rbu re- rea reb ree reg reo rer reu rga rgb rge rgg rgo rgr roa rob roe rog roo ror rou rra rrb rrg rrr rru rua rub rue rug ruo rur ruu ua- uaa uab uae uag uao uar uau uba ubb ube ubg ubo ubr ubu uea ueb uee ueg uer uga ugb uge ugg ugo ugr ugu uoa uob uoe uog uoo uor ur- ura urb ure urg uro urr uru uua uue uug uur uuu