???????
      +--------
MXQXF | FFFQMLH
       -MXQXF
        =====
        NPPMFL
       - MXQXF
        ======
         HJPNQH
        -PQTNTX
         ======
         ??????

base: 11
letters: EFHJLMNPQTX
difficulty: medium
missing: E