iii iio iir iis iix io- ioi ioo ior ios ir- iri iro irr irs irx iry is- isi iso isr iss isy ixi ixy iyo iyr iys iyy o-i oii oio oir ois oo- ooi ooo oor oos oox or- ori oro orr ors orx ory os- osi oso osr oss osx ox- oxi oxo oxx oxy oyi oyo oys rii rio rir ris rix riy roi roo ror ros rox roy rri rrr rrs rsi rso rsr rss rsx rxr rxs ry- ryo ryr rys ryy sii sio sir sis six soi soo sor sos sox soy sr- sri sro srr srs srx sry ss- ssi sso ssr sss ssx sxi sxs sy- syi syr sys syx xii xio xis xix xoi xoo xor xos xox xrx xry xsi xss xxi xxo xxx xxy xyr xyy yii yio yir yis yoi yoo yor yos yox yoy yro yrs ysi yso ysr yss ysy yxy yys yyy