ECWF
      ----------
 FWFF ) ECNTQXCQ
       -XFHFC
        =====
         CWTEX
        -HFXFE
         =====
          WWEFC
         -CFTFX
          =====
           FXQNQ
          -WFQFT
           =====
            XFNF

base: 10
symbols: CEFHNQTWXY
difficulty: intermediate
missing: Y