c-- ccc cce ccf cco cct ccx ce- cec cee cef ceo cet cex cfc cfe cff cfo cft cfx co- coc coe cof coo cot cox ctc cte ctf cto ctt ctx cxc cxf cxo cxt cxx ec- ecc ece ecf eco ect ecx eec eee eef eeo eet eex ef- efc efe eff efo eft efx eo- eoc eoe eof eoo eot etc ete etf eto ett etx ex- exc exe exo ext exx fcc fce fcf fco fct fcx fec fee fef feo fet fex ffc ffe fff ffo fft ffx foc foe fof foo fot fox ftc fte ftf fto ftt ftx fxe fxt fxx oc- occ ocf oco oct ocx oec oee oef oeo oet oex of- ofc ofe off ofo oft ofx oo- ooc oof ooo oot oox ot- otc ote otf oto ott ox- oxc oxf oxo oxt oxx t-x tcc tce tcf tco tct tcx te- tec tee tef teo tet tex tfc tfe tff tfo tft tfx to- toc toe tof too tot tox ttc tte ttf tto ttt ttx txe txf txt xcf xcx xee xet xex xfe xft xfx xoc xof xoo xot xox xtc xtf xtx xxo xxx