-ous ffff ffrr ffss fftf fofo foof foos foot for- foro forr fors fort foso foss fost foto fots fott four fous fout fros frot frou frso frst fsfo fssf ftos ftrs ftsr fuff fufu fuor fur- furo furr furs furt fuso fuss fust fusu futo futs futu off- offo offr offs offu ofor ofst ofus ooff oofs oooo ooos oort oost oots oous orff orfs orfu oro- orof oror oros orot orro orrs orso orsu orto orts orus osoo osor osos osro osso ossu ostr osts oto- otof otoo otor otos otro otrs otso otsu otto otts ottu otur otus ouff our- ouro ours ourt oust out- outo outs ouu- roff rofo roof roor roos root roro rort roru roso ross rost roto rotr rots rott rouf rous rout rrrr rsos rsts rstu rtss rtts ruff rufo ruft ruro rurs ruru ruso russ rust rusu ruto ruts rutt rutu s-os sfor sfos sfro sfss sfsu sfts sofo soft soof soor soos soot soro sorr sors sort soru soso soss sost soto sots sotu souf sour sous sout sros srtr ssot ssrs sssf ssss ssts stfu stof stoo stor stos stot stou stro strs stru stsf stss sttr stuf stur stus stut suf- suff sufr sufs sufu suor suos sur- surf suro surr surs surt suru sus- suso suss sust susu suto sutu suus tfot tfrs tfss toff tofo toft tofu toof toor toos toot torf toro torr tors tort toru toso toss tost tosu toto totr tots tott tour tous tout trfr troo tros trot trou trst trtr trus trut truu tsos tsou tssf tssr tsst tsts ttff ttss tttt tuff tufo tuft tufu tuor tuos turf turo turr turs turt turu tuss tust tuto tuts tutt tutu tuuo ufos uofo uor- urff urft uro- uroo urso urss ursu urts urur urus urut usfs usos ussf ussr usss usst ussu usto usts usus utfo utor utto uttu uutf uuuu