???????
      +--------
0860A | CF49A32
       -7D9F9
        =====
        ADB473
       -A9A4BD
        ======
         BA51B2
        -ACBB16
         ======
         ??????

base: 16
letters: 0123456789ABCDEF
difficulty: hard
hints: 6 << 2, 1 << E
missing: E