fff ffi ffn ffp ffs fif fii fin fip fis fnf fni fnn fnp fns fpi fpn fpp fps fsf fsi fsn fsp fss i-f iff ifi ifn ifp ifs iif iii iin iip iis in- inf ini inn inp ins ipf ipi ipn ipp ips is- isf isi isn isp iss n-i nff nfi nfn nfp nfs nif nii nin nip nis nnf nni nnn nnp nns npf npi npn npp nps nsf nsi nsn nsp nss p-p pff pfi pfn pfp pfs pif pii pin pip pis pn- pnf pni pnn pnp pns ppf ppi ppn ppp pps ps- psf psi psn psp pss sff sfi sfn sfp sfs sif sii sin sip sis snf sni snn snp sns spf spi spn spp sps ss- ssf ssi ssn ssp sss