PLN
      +--------
PGXUH | XQLGMTQ
       -RGFXM
        =====
        PHHFET
       -PQTRLG
        ======
          ULMUQ
         -XGERX
          =====
          MGMFL

base: 13
letters: EFGHLMNPQRTUX
difficulty: hard
missing: N