a-a a-t aaa aaf aao aas aat aax af- afa aff afo afs aft afx aoa aof aoo aos aot aox as- asa asf aso ass ast asx at- ata atf ato ats att atx ax- axa axo axs axt axx faa faf fao fas fat fax ffa fff ffo ffs fft ffx foa fof foo fos fot fox fsa fsf fso fss fst fsx fta ftf fto fts ftt ftx fxs fxt fxx oaa oaf oao oas oat oax of- ofa off ofo ofs oft ofx oo- ooa oof ooo oos oot oox os- osa osf oso oss ost osx ot- ota otf oto ots ott ox- oxa oxf oxo oxt oxx saa saf sao sas sat sax sfa sff sfo sfs sft sfx soa sof soo sos sot sox ss- ssa ssf sso sss sst ssx sta stf sto sts stt stx sxs sxt t-x taa taf tao tas tat tax tfa tff tfo tfs tft tfx to- toa tof too tos tot tox tsa tsf tso tss tst tsx tta ttf tto tts ttt ttx txf txs txt xaa xaf xas xat xfa xfs xft xfx xoa xof xoo xos xot xox xsa xss xst xtf xts xtx xxo xxx