i-v iii iio iip iis iit io- ioi ioo iop ios iot iov ipi ipo ipp ips ipt ipv is- isi iso isp iss ist isv iti ito itp its itt itv ivi ivo ivp ivs ivt ivv o-i oii oio oip ois oit oiv oo- ooi ooo oop oos oot oov op- opi opo opp ops opt opv os- osi oso osp oss ost osv ot- oti oto otp ots ott otv ov- ovi ovo ovp ovs ovv p-p pii pio pip pis pit piv poi poo pop pos pot pov ppi ppo ppp pps ppt ppv ps- psi pso psp pss pst psv pt- pti pto ptp pts ptt ptv pvi pvo pvp pvs pvt pvv sii sio sip sis sit siv soi soo sop sos sot sov spi spo spp sps spt spv ss- ssi sso ssp sss sst ssv sti sto stp sts stt stv svi svo svp svs svt svv tii tio tip tis tit tiv to- toi too top tos tot tov tpi tpo tpp tps tpt tpv tsi tso tsp tss tst tsv tti tto ttp tts ttt ttv tvi tvo tvp tvs tvt vi- vii vio vip vis vit viv voi voo vop vos vot vov vpi vpo vpp vps vpt vsi vso vsp vss vst vsv vti vto vts vtt vtv vvi vvo vvs vvt vvv