iii iip iis iit ipi ipp ips ipt ipy is- isi isp iss ist isy iti itp its itt ity iys iyt iyy p-p pii pip pis pit ppi ppp pps ppt ps- psi psp pss pst psy pt- pti ptp pts ptt pty py- pys pyt sii sip sis sit spi spp sps spt spy ss- ssi ssp sss sst sti stp sts stt sty sy- syi syp sys syt tii tip tis tit tiy tpi tpp tps tpt tsi tsp tss tst tsy tti ttp tts ttt tty typ tys tyt yii yip yis yit yps ysi ysp yss yst ysy ytp yts ytt yys yyt yyy