????????
      +---------
MNYRF | GGNGHNNU
       -GWEFG
        =====
         XWYRN
        -MNYRF
         =====
         MFTTMN
        -MMERUJ
         ======
          MXNXGU
         -MMERUJ
          ======
          ??????

base: 14
letters: EFGHJMNPRTUWXY
difficulty: medium
missing: P