-er eee eeo eer ees eex eie eii eio eir eis eix eo- eoe eoi eoo eor eos ere eri ero err ers es- ese esi eso esr ess esx ex- exe exi exo exr exs exx ie- iee iei ier ies iex iie iii iio iir iis iix io- ioe ioi ioo ior ios ir- ire iri iro irr irs irx is- ise isi iso isr iss ixe ixi o-i oee oei oeo oer oes oex oie oii oio oir ois oo- ooi ooo oor oos oox or- ore ori oro orr ors orx os- ose osi oso osr oss osx ox- oxi oxo oxx re- ree rei reo rer res rex rie rii rio rir ris rix roe roi roo ror ros rox rri rrr rrs rse rsi rso rsr rss rsx rxr rxs se- see sei seo ser ses sex sie sii sio sir sis six soe soi soo sor sos sox sr- sre sri sro srr srs srx ss- sse ssi sso ssr sss ssx sxi sxs xee xer xes xex xie xii xio xis xix xoi xoo xor xos xox xrx xsi xss xxi xxo xxx