upnst punst unpst nupst pnust npust upsnt pusnt uspnt supnt psunt spunt unspt nuspt usnpt sunpt nsupt snupt pnsut npsut psnut spnut nsput snput upnts punts unpts nupts pnuts nputs uptns putns utpns tupns ptuns tpuns untps nutps utnps tunps ntups tnups pntus nptus ptnus tpnus ntpus tnpus upstn pustn usptn suptn psutn sputn uptsn putsn utpsn tupsn ptusn tpusn ustpn sutpn utspn tuspn stupn tsupn pstun sptun ptsun tpsun stpun tspun unstp nustp usntp suntp nsutp snutp untsp nutsp utnsp tunsp ntusp tnusp ustnp sutnp utsnp tusnp stunp tsunp nstup sntup ntsup tnsup stnup tsnup pnstu npstu psntu spntu nsptu snptu pntsu nptsu ptnsu tpnsu ntpsu tnpsu pstnu sptnu ptsnu tpsnu stpnu tspnu nstpu sntpu ntspu tnspu stnpu tsnpu
Note: these 'words' (valid or invalid) are all the permutations of the word upnst. These words are obtained by scrambling the letters in upnst.