????????
      +---------
PJLLE | FQMWWQYF
       -PJLLE
        =====
        PLYTMQ
       -PQPFYW
        ======
         EQJQPY
        -EEMFFL
         ======
          EEUTPF
         - FWRRQ
          ======
          ??????

base: 13
letters: EFJLMNPQRTUWY
difficulty: medium
missing: N