?????????
      +----------
LQJWJ | LEPUMPXFM
       -LQJWJ
        =====
         ETXEPX
        -EEQXTX
         ======
          UMTJQF
         -HTQTUN
          ======
           HNWMTM
          -HWQNXL
           ======
           ??????

base: 14
letters: EFHJLMNPQTUWXY
missing: Y
difficulty: hard
hints: Y << M, H << L