oo- ooo oop oor oos oot oov op- opo opp opr ops opt opv or- oro orp orr ors ort orv os- oso osp osr oss ost osv ot- oto otp otr ots ott otv ov- ovo ovp ovs ovv p-p poo pop por pos pot pov ppo ppp ppr pps ppt ppv pro prp prr prs prt prv ps- pso psp psr pss pst psv pt- pto ptp ptr pts ptt ptv pvo pvp pvr pvs pvt pvv roo rop ror ros rot rov rpo rpp rpr rps rpt rpv rrp rrr rrs rrt rso rsp rsr rss rst rsv rto rtp rtr rts rtt rtv rvo rvp rvr rvs rvt rvv soo sop sor sos sot sov spo spp spr sps spt spv sr- sro srp srr srs srt srv ss- sso ssp ssr sss sst ssv sto stp str sts stt stv svo svp svr svs svt svv to- too top tor tos tot tov tpo tpp tpr tps tpt tpv tro trp trr trs trt trv tso tsp tsr tss tst tsv tto ttp ttr tts ttt ttv tvo tvp tvr tvs tvt voo vop vor vos vot vov vpo vpp vpr vps vpt vrp vrr vrs vrt vso vsp vsr vss vst vsv vto vtr vts vtt vtv vvo vvr vvs vvt vvv