nnnn nnpr nnss nntn nprt npss nptn nrpn nrps nrsp nrts nsnr nsps nssp nssr nsss nstp nsts ntss nttr pnpp pntr pppn pppp ppps ppss pptn ppts pptt prnp prps prrs prss prtp prtr psnr pspp pspr psps psrp psst psts rnnt rnsp rntp rppn rpps rptn rpts rrrr rrsp rsnn rsnr rsps rstp rsts rtns rtps rtss rttp rtts snns snpp snrs sntr spns spps sprs spsp spss spst sptr spts srnn srps srpt srsp srtp srtr ssns ssps sspt ssrs ssss sstp ssts stnn stnr stns stpp stps strn strs stss sttr tnsp tnts tppp tppr tprs tptp tptr trpn trpp trps trst trtr tspn tsps tspt tssr tsst tsts ttss tttt