bbb bbf bbi bbo bbt bfb bff bfi bfo bft bi- bib bif bii bio bit bob bof boi boo bot btb btf bti bto btt fbb fbf fbi fbo fbt fff ffi ffo fft fib fif fii fit fob fof foi foo fot ftb ftf fti fto ftt i-f ibb ibf ibi ibo ibt ifb iff ifi ifo ift iib iif iii iio iit io- iob iof ioi ioo iot itb itf iti ito itt o-i ob- obb obf obi obo obt of- ofb off ofi ofo oft oib oif oii oio oit oo- oob oof ooi ooo oot ot- otb otf oti oto ott tbb tbf tbi tbo tbt tfb tff tfi tfo tft tib tif tii tio tit to- tob tof toi too tot ttb ttf tti tto ttt