fff ffi ffn ffs fft fif fii fin fis fit fnf fni fnn fns fnt fsf fsi fsn fss fst ftf fti ftn fts ftt i-f iff ifi ifn ifs ift iif iii iin iis iit in- inf ini inn ins int is- isf isi isn iss ist itf iti itn its itt n-i nff nfi nfn nfs nft nif nii nin nis nit nnf nni nnn nns nnt nsf nsi nsn nss nst ntf nti ntn nts ntt sff sfi sfn sfs sft sif sii sin sis sit snf sni snn sns snt ss- ssf ssi ssn sss sst stf sti stn sts stt tff tfi tfn tfs tft tif tii tin tis tit tnf tni tnn tns tnt tsf tsi tsn tss tst ttf tti ttn tts ttt