fff ffi ffo ffs ffu fif fii fis fiu fof foi foo fos fou fsf fsi fso fss fsu fuf fui fuo fus fuu i-f iff ifi ifo ifs ifu iif iii iio iis iiu io- iof ioi ioo ios iou is- isf isi iso iss isu iu- iui ius o-i of- off ofi ofo ofs ofu oif oii oio ois oiu oo- oof ooi ooo oos os- osf osi oso oss osu ou- ouf oui ouo ous sff sfi sfo sfs sfu sif sii sio sis siu sof soi soo sos sou ss- ssf ssi sso sss ssu suf sui suo sus suu uff ufi ufo ufs ufu uif uii uio uis uiu uoo uos usf usi uso uss usu uus uuu