AHQF
      ----------
 FQFF ) AHWXYEHY
       -EFCFH
        =====
         HQXAE
        -CFEFA
         =====
          QQAFH
         -HFXFE
          =====
           FEYWY
          -QFYFX
           =====
            EFWF

base: 10
symbols: ACEFHQUWXY
difficulty: intermediate
missing: U