D403
      +---------
D6953 | 9E6AE071
       -D6953
        =====
         7E410
        -05C47
         =====
         D22087
        -D176E5
         ======
           BD1A1
          -28B7D
           =====
           DD603

base: 15
letters: 0123456789ABCDE
difficulty: hard