fff ffi ffk ffn ffo ffs fif fii fik fin fis fkf fki fkk fnf fni fnk fnn fns fof foi fok fon foo fos fsf fsi fsk fsn fso fss i-f iff ifi ifn ifo ifs iif iii iin iio iis ikf iki ikk iko iks in- inf ini ink inn ino ins io- iof ioi ion ioo ios is- isf isi isk isn iso iss kff kfi kfo kfs kif kii kik kin kio kis kki kkk kkn kks kn- knf kni knk knn kno kof koi kok kon koo kos ksf ksi ksk ksn kso kss n-i nff nfi nfk nfn nfo nfs nif nii nik nin nio nis nkf nki nkk nkn nko nks nnf nni nnk nnn nno nns no- nof noi nok non noo nos nsf nsi nsk nsn nso nss o-i of- off ofi ofn ofo ofs oif oii oik oin oio ois oki okk oko oks on- onf oni onk onn ono ons oo- oof ooi ook oon ooo oos os- osf osi osk osn oso oss sff sfi sfk sfn sfo sfs sif sii sik sin sio sis sk- skf ski skk sko sks snf sni snk snn sno sns sof soi sok son soo sos ss- ssf ssi ssk ssn sso sss