eee eef een eeo eep ees ef- efe eff efo efp efs en- ene enf enn eno enp ens eo- eoe eof eon eoo eop eos ep- epe epf epn epo epp eps es- ese esf esn eso esp ess fee fef fen feo fep fes ffe fff ffn ffo ffp ffs fne fnf fnn fnp fns foe fof fon foo fop fos fpe fpn fpo fpp fps fse fsf fsn fso fsp fss ne- nee nef nen neo nep nes nfe nff nfn nfo nfp nfs nne nnf nnn nno nnp nns no- noe nof non noo nop nos npe npf npn npo npp nps nse nsf nsn nso nsp nss oee oef oen oeo oep oes of- ofe off ofn ofo ofp ofs on- one onf onn ono onp ons oo- oof oon ooo oop oos op- ope opf opn opo opp ops os- ose osf osn oso osp oss p-p pee pef pen peo pep pes pfe pff pfn pfo pfp pfs pn- pne pnf pnn pno pnp pns poe pof pon poo pop pos ppe ppf ppn ppo ppp pps ps- pse psf psn pso psp pss se- see sef sen seo sep ses sfe sff sfn sfo sfp sfs sne snf snn sno snp sns soe sof son soo sop sos spe spf spn spo spp sps ss- sse ssf ssn sso ssp sss