oo- ooo oor oos oot or- oro orr ors ort ory os- oso osr oss ost ot- oto otr ots ott oyo oys roo ror ros rot roy rrr rrs rrt rso rsr rss rst rto rtr rts rtt rty ry- ryo ryr rys ryy soo sor sos sot soy sr- sro srr srs srt sry ss- sso ssr sss sst sto str sts stt sty sy- syr sys syt to- too tor tos tot toy tro trr trs trt try tso tsr tss tst tsy tto ttr tts ttt tty tyo tyr tys tyt yoo yor yos yot yoy yro yrs yrt yso ysr yss yst ysy yto ytr yts ytt yys yyt yyy