fff ffk ffo ffr ffs ffw fkf fkk fof fok foo for fos fow frf frk fro frr frs frw fsf fsk fso fsr fss fsw fwf fwo fws kff kfo kfs kfw kkk kkr kks kof kok koo kor kos kow krf krk kro krr krs krw ksf ksk kso ksr kss ksw kw- kwf kwk kwo kws kww of- off ofo ofr ofs ofw okk oko okr oks okw oo- oof ook ooo oor oos oow or- orf ork oro orr ors os- osf osk oso osr oss osw owf owk owo ows oww rff rfk rfo rfr rfs rfw rkf rkk rko rks rof rok roo ror ros row rrf rrk rrr rrs rsf rsk rso rsr rss rsw rwf rwr rws sff sfk sfo sfr sfs sfw sk- skf skk sko skr sks skw sof sok soo sor sos sow sr- srf srk sro srr srs srw ss- ssf ssk sso ssr sss ssw swf swk swo swr sws wff wfk wfo wfr wfs wfw wkf wko wkr wks wkw wof wok woo wor wos wow wr- wrf wrk wro wrr wrs wrw wsf wsk wso wsr wss wsw wwf wwo www