????????
      +---------
LJWFY | QFRQRTTF
       -LJWFY
        =====
         RRJQT
        -YEJNM
         =====
         LGWGYT
        -LMQMYF
         ======
          LELXRF
         -LEXFJE
          ======
          ??????

base: 13
letters: EFGJLMNQRTWXY
difficulty: hard