1904
      +---------
D11B1 | 84439A7D
       -2F9BF
        =====
        E7205A
       -E96150
        ======
         129877
        -1975E9
         ======
          570A1D
         -573BFC
          ======
            BEF8

base: 16
letters: 0123456789ABCDEF
difficulty: hard