fff ffm ffr ffs ffu fmf fmm fmr fms fmu frf frm frr frs fru fsf fsm fsr fss fsu fuf fum fur fus fuu m-f m-r mff mfm mfr mfs mfu mmf mmm mmr mms mmu mrf mrm mrr mrs mru msf msm msr mss msu muf mum mur mus muu rff rfm rfr rfs rfu rmf rmm rmr rms rrf rrm rrr rrs rru rsf rsm rsr rss rsu ruf rum rur rus ruu sff sfm sfr sfs sfu smf smm smr sms smu sr- srf srm srr srs ss- ssf ssm ssr sss ssu suf sum sur sus suu uff ufm ufr ufs ufu um- umf umm umr ums umu ur- urf urm urr urs uru usf usm usr uss usu uum uur uus uuu