oo- ooo oor oos oot or- oro orr ors ort orz os- oso osr oss ost ot- oto otr ots ott otz ozo ozs ozt ozz roo ror ros rot roz rrr rrs rrt rso rsr rss rst rto rtr rts rtt rtz rzo soo sor sos sot soz sr- sro srr srs srt ss- sso ssr sss sst ssz sto str sts stt stz szr to- too tor tos tot toz tro trr trs trt trz tso tsr tss tst tto ttr tts ttt tzs zo- zoo zor zos zot zro zrs zst zsz ztr zzr zzs zzt zzz