HMXQ
      +---------
FMJRU | URQQJFEF
       -UFQMX
        =====
         UPRHF
        -MXEYH
         =====
         FFXRYE
        -FPEFMF
         ======
          FJUURF
         -FFQMXR
          ======
            RFER

base: 11
letters: EFHJMPQRUXY
difficulty: medium