iii iip iis iit iix ipi ipp ips ipt ipx ipy is- isi isp iss ist isy iti itp its itt itx ity ixi ixy iys iyt iyy p-p pii pip pis pit pix ppi ppp pps ppt ppx ps- psi psp pss pst psx psy pt- pti ptp pts ptt ptx pty pxs pxt py- pys pyt pyx sii sip sis sit six spi spp sps spt spx spy ss- ssi ssp sss sst ssx sti stp sts stt stx sty sxi sxs sxt sy- syi syp sys syt syx t-x tii tip tis tit tix tiy tpi tpp tps tpt tpx tsi tsp tss tst tsx tsy tti ttp tts ttt ttx tty txi txs txt typ tys tyt xii xis xit xix xpp xps xpt xsi xsp xss xst xti xtp xts xtx xty xxi xxp xxx xxy xyp xyy yii yip yis yit yps ysi ysp yss yst ysy ytp yts ytt yxy yys yyt yyy