XMJW
      +---------
UTRML | LPHHZZPY
       -UTRML
        =====
        XGXLQZ
       -XQLYJY
        ======
          HJUHP
         -RXPUP
          =====
          XLLZNY
         -XNPQWJ
          ======
           UVUGG

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