????????
      +---------
RPJGE | QGUXUNHN
       -RPJGE
        =====
        EWWTEN
       -ERQPHX
        ======
         REJQWH
        -UTPJMT
         ======
          UUGNQN
         -UMNRTJ
          ======
          ??????

base: 13
letters: EGHJMNPQRTUWX
difficulty: hard