E17
      +--------
02563 | 26763C5
       -AE183
        =====
        D16E4C
       -DB80E5
        ======
         DEDA85
        -DDC5B4
         ======
          00705

base: 15
letters: 0123456789ABCDE
difficulty: hard
hints: 1 << 6, 1 << C, 5 << A
missing: 9