ffff ffrr fftf fofo foof foot fopp for- foro forr fort foto fotp fott fprf frop frot ftop off- offo offr ofor oftp ooff oooo oort ootp opo- opor oppo opto orff oro- orof oror orot orro orto otfp oto- otof otoo otor otpp otro otto pfff pffr pfft poff poof poop poor poot pop- popo popp popt poro porr port potf poto pott pppo pppp pprf pptt pro- prof proo prop prot prtp prtr ptop ptrf roff rofo roof roop roor root ropo roro rort roto rotr rott rpof rrrr rttp tfot tfpt tftp toff tofo toft toof toor toot top- topf topo topp topt torf toro torp torr tort toto totr tott tppp tppr tptp tptr trfr troo trop trot trpp trtr ttff ttop tttt