????????
      +---------
PPNNH | PFXNQQYY
       -PPNNH
        =====
         JEWFQ
        -JJPMW
         =====
          TYMQY
         -JJPMW
          =====
          NRNEYY
         -NHFXNW
          ======
          ??????

base: 14
letters: EFGHJMNPQRTWXY
difficulty: challenging
missing: G