a-a a-b a-i a-t aaa aab aaf aai aao aat ab- aba abb abf abi abo abt af- afa afb aff afi afo aft ai- aia aib aif aii aio ait aoa aob aof aoi aoo aot at- ata atb atf ati ato att baa bab baf bai bao bat bba bbb bbf bbi bbo bbt bfa bfb bff bfi bfo bft bi- bia bib bif bii bio bit boa bob bof boi boo bot bta btb btf bti bto btt faa fab faf fai fao fat fba fbb fbf fbi fbo fbt ffa fff ffi ffo fft fia fib fif fii fit foa fob fof foi foo fot fta ftb ftf fti fto ftt i-f ia- iaa iab iaf iai iao iat iba ibb ibf ibi ibo ibt ifa ifb iff ifi ifo ift iia iib iif iii iio iit io- ioa iob iof ioi ioo iot ita itb itf iti ito itt o-i oaa oab oaf oai oao oat ob- oba obb obf obi obo obt of- ofa ofb off ofi ofo oft oia oib oif oii oio oit oo- ooa oob oof ooi ooo oot ot- ota otb otf oti oto ott taa tab taf tai tao tat tba tbb tbf tbi tbo tbt tfa tfb tff tfi tfo tft tia tib tif tii tio tit to- toa tob tof toi too tot tta ttb ttf tti tto ttt