QRZ
      +--------
NZNWR | UUZXVPN
       -TJQRM
        =====
        NUXLYP
       -NTVQZV
        ======
          GXLQN
         -GJPWZ
          =====
           UPPV

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard
missing: H