????????
      +---------
MNJFP | MFMMUMPU
       -MNJFP
        =====
         RQJRM
        -MNJFP
         =====
         LMHJEP
        -LLULRE
         ======
          LNNUJU
         -LRHQGM
          ======
          ??????

base: 13
letters: EFGHJLMNPQRUY
difficulty: medium
hints: G << P
missing: Y