????????
      +---------
YUGLR | REYMYGYW
       -YUGLR
        =====
        LNLWFG
       -LGNUGM
        ======
         YJRWEY
        -YQYWJU
         ======
          JPQYWW
         -PEMFEJ
          ======
          ??????

base: 13
letters: EFGJLMNPQRUWY
difficulty: hard