fff ffi ffn ffo ffr ffx fif fii fin fir fix fnf fni fnn fnr fnx fof foi fon foo for fox frf fri frn fro frr fxi fxr fxx i-f iff ifi ifn ifo ifr ifx iif iii iin iio iir iix in- inf ini inn ino inr inx io- iof ioi ion ioo ior ir- irf iri irn iro irr irx ixi ixn n-i nff nfi nfn nfo nfr nif nii nin nio nir nix nnf nni nnn nno no- nof noi non noo nor nox nrf nri nrn nro nrr nrx o-i of- off ofi ofn ofo ofr ofx oif oii oin oio oir on- onf oni onn ono onr onx oo- oof ooi oon ooo oor oox or- orf ori orn oro orr orx ox- oxf oxi oxn oxo oxx rff rfi rfn rfo rfr rif rii rin rio rir rix rni rnn rno rnr rof roi ron roo ror rox rrf rri rrn rrr rxr xfn xfx xii xin xio xix xno xof xoi xon xoo xor xox xrf xrx xxi xxo xxx