a-a a-t aaa aaf aao aar aat aax af- afa aff afo afr aft afx aoa aof aoo aor aot aox ar- ara arf aro arr art arx at- ata atf ato atr att atx ax- axa axo axr axt axx faa faf fao far fat fax ffa fff ffo ffr fft ffx foa fof foo for fot fox fra frf fro frr frt fta ftf fto ftr ftt ftx fxr fxt fxx oaa oaf oao oar oat oax of- ofa off ofo ofr oft ofx oo- ooa oof ooo oor oot oox or- ora orf oro orr ort orx ot- ota otf oto otr ott ox- oxa oxf oxo oxt oxx ra- raa raf rao rar rat rax rfa rff rfo rfr rft roa rof roo ror rot rox rra rrf rrr rrt rta rtf rto rtr rtt rtx rxr t-x taa taf tao tar tat tax tfa tff tfo tfr tft tfx to- toa tof too tor tot tox tra trf tro trr trt trx tta ttf tto ttr ttt ttx txf txt xaa xaf xar xat xfa xft xfx xoa xof xoo xor xot xox xrf xrt xrx xtf xtr xtx xxo xxx