fff ffm ffo ffp ffr ffs fmf fmm fmo fmp fmr fms fof fom foo fop for fos fpm fpo fpp fpr fps frf frm fro frp frr frs fsf fsm fso fsp fsr fss m-f m-o m-r mff mfm mfo mfp mfr mfs mmf mmm mmo mmp mmr mms mof mom moo mop mor mos mpf mpm mpo mpp mpr mps mrf mrm mro mrp mrr mrs msf msm mso msp msr mss of- off ofm ofo ofp ofr ofs om- omf omm omo omp omr oms oo- oof oom ooo oop oor oos op- opf opm opo opp opr ops or- orf orm oro orp orr ors os- osf osm oso osp osr oss p-p pff pfm pfo pfp pfr pfs pmf pmm pmo pmp pmr pms pof pom poo pop por pos ppf ppm ppo ppp ppr pps prf prm pro prp prr prs ps- psf psm pso psp psr pss rff rfm rfo rfp rfr rfs rmf rmm rmo rmp rmr rms rof rom roo rop ror ros rpf rpm rpo rpp rpr rps rrf rrm rrp rrr rrs rsf rsm rso rsp rsr rss sff sfm sfo sfp sfr sfs smf smm smo smp smr sms sof som soo sop sor sos spf spm spo spp spr sps sr- srf srm sro srp srr srs ss- ssf ssm sso ssp ssr sss