????????
      +---------
LGJNX | NRXTNJGT
       -TMPWG
        =====
        LYMUUJ
       - PFUNG
        ======
         LUYXNG
        -LRRXHX
         ======
          LRJWXT
         -LRRXHX
          ======
          ??????

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: intermediate
missing: Q