-er eee eeo eer ees eex eo- eoe eoo eor eos eou ere ero err ers eru es- ese eso esr ess esu esx eu- eue eur eus eux ex- exe exo exr exs exu exx oee oeo oer oes oex oo- ooo oor oos oox or- ore oro orr ors oru orx os- ose oso osr oss osu osx ou- oue ouo our ous ox- oxo oxx re- ree reo rer res reu rex roe roo ror ros rou rox rrr rrs rru rse rso rsr rss rsu rsx rue ruo rur rus ruu rux rxr rxs se- see seo ser ses seu sex soe soo sor sos sou sox sr- sre sro srr srs srx ss- sse sso ssr sss ssu ssx sue suo sur sus suu sux sxs sxu uee uer ues uoe uoo uor uos uox ur- ure uro urr urs uru urx use uso usr uss usu usx uue uur uus uuu uxo uxr uxu xee xer xes xeu xex xoo xor xos xox xrx xss xue xus xxo xxx