fff ffn ffo ffp ffs fnf fnn fnp fns fof fon foo fop fos fpn fpo fpp fps fsf fsn fso fsp fss nff nfn nfo nfp nfs nnf nnn nno nnp nns no- nof non noo nop nos npf npn npo npp nps nsf nsn nso nsp nss of- off ofn ofo ofp ofs on- onf onn ono onp ons oo- oof oon ooo oop oos op- opf opn opo opp ops os- osf osn oso osp oss p-p pff pfn pfo pfp pfs pn- pnf pnn pno pnp pns pof pon poo pop pos ppf ppn ppo ppp pps ps- psf psn pso psp pss sff sfn sfo sfp sfs snf snn sno snp sns sof son soo sop sos spf spn spo spp sps ss- ssf ssn sso ssp sss