fitsn iftsn ftisn tfisn itfsn tifsn fistn ifstn fsitn sfitn isftn siftn ftsin tfsin fstin sftin tsfin stfin itsfn tisfn istfn sitfn tsifn stifn fitns iftns ftins tfins itfns tifns fints ifnts fnits nfits infts nifts ftnis tfnis fntis nftis tnfis ntfis itnfs tinfs intfs nitfs tnifs ntifs fisnt ifsnt fsint sfint isfnt sifnt finst ifnst fnist nfist infst nifst fsnit sfnit fnsit nfsit snfit nsfit isnft sinft insft nisft snift nsift ftsni tfsni fstni sftni tsfni stfni ftnsi tfnsi fntsi nftsi tnfsi ntfsi fsnti sfnti fnsti nfsti snfti nsfti tsnfi stnfi tnsfi ntsfi sntfi nstfi itsnf tisnf istnf sitnf tsinf stinf itnsf tinsf intsf nitsf tnisf ntisf isntf sintf instf nistf snitf nsitf tsnif stnif tnsif ntsif sntif nstif
Note: these 'words' (valid or invalid) are all the permutations of the word fitsn. These words are obtained by scrambling the letters in fitsn.