????????
      +---------
EMJHL | UUXMHLFQ
       -WJWFN
        =====
        QMHEWL
       - NULJE
        ======
         MUNMQF
        -MWMPGX
         ======
          QWWQPQ
         -QWXQPM
          ======
          ??????

base: 13
letters: EFGHJLMNPQUWX
difficulty: hard