????????
      +---------
XXLEN | MEFELTER
       -RRELX
        =====
        LTEPHT
       -LEXJHL
        ======
         XYFYJE
        -PMHXYT
         ======
           RRNRR
          -RRELX
           =====
           ?????

base: 12
letters: EFHJLMNPRTXY
difficulty: intermediate