fff ffi ffn ffo ffp ffr ffs fif fii fin fip fir fis fnf fni fnn fnp fnr fns fof foi fon foo fop for fos fpi fpn fpo fpp fpr fps frf fri frn fro frp frr frs fsf fsi fsn fso fsp fsr fss i-f iff ifi ifn ifo ifp ifr ifs iif iii iin iio iip iir iis in- inf ini inn ino inp inr ins io- iof ioi ion ioo iop ior ios ipf ipi ipn ipo ipp ipr ips ir- irf iri irn iro irp irr irs is- isf isi isn iso isp isr iss n-i nff nfi nfn nfo nfp nfr nfs nif nii nin nio nip nir nis nnf nni nnn nno nnp nns no- nof noi non noo nop nor nos npf npi npn npo npp npr nps nrf nri nrn nro nrp nrr nrs nsf nsi nsn nso nsp nsr nss o-i of- off ofi ofn ofo ofp ofr ofs oif oii oin oio oip oir ois on- onf oni onn ono onp onr ons oo- oof ooi oon ooo oop oor oos op- opf opi opn opo opp opr ops or- orf ori orn oro orp orr ors os- osf osi osn oso osp osr oss p-p pff pfi pfn pfo pfp pfr pfs pif pii pin pio pip pir pis pn- pnf pni pnn pno pnp pnr pns pof poi pon poo pop por pos ppf ppi ppn ppo ppp ppr pps prf pri prn pro prp prr prs ps- psf psi psn pso psp psr pss rff rfi rfn rfo rfp rfr rfs rif rii rin rio rip rir ris rni rnn rno rnp rnr rns rof roi ron roo rop ror ros rpf rpi rpn rpo rpp rpr rps rrf rri rrn rrp rrr rrs rsf rsi rsn rso rsp rsr rss sff sfi sfn sfo sfp sfr sfs sif sii sin sio sip sir sis snf sni snn sno snp snr sns sof soi son soo sop sor sos spf spi spn spo spp spr sps sr- srf sri srn sro srp srr srs ss- ssf ssi ssn sso ssp ssr sss