fff ffi ffn ffo ffr ffs fif fii fin fir fis fnf fni fnn fnr fns fof foi fon foo for fos frf fri frn fro frr frs fsf fsi fsn fso fsr fss i-f iff ifi ifn ifo ifr ifs iif iii iin iio iir iis in- inf ini inn ino inr ins io- iof ioi ion ioo ior ios ir- irf iri irn iro irr irs is- isf isi isn iso isr iss n-i nff nfi nfn nfo nfr nfs nif nii nin nio nir nis nnf nni nnn nno nns no- nof noi non noo nor nos nrf nri nrn nro nrr nrs nsf nsi nsn nso nsr nss o-i of- off ofi ofn ofo ofr ofs oif oii oin oio oir ois on- onf oni onn ono onr ons oo- oof ooi oon ooo oor oos or- orf ori orn oro orr ors os- osf osi osn oso osr oss rff rfi rfn rfo rfr rfs rif rii rin rio rir ris rni rnn rno rnr rns rof roi ron roo ror ros rrf rri rrn rrr rrs rsf rsi rsn rso rsr rss sff sfi sfn sfo sfr sfs sif sii sin sio sir sis snf sni snn sno snr sns sof soi son soo sor sos sr- srf sri srn sro srr srs ss- ssf ssi ssn sso ssr sss