A205
      +---------
803EF | 9599F5D0
       -803EF
        =====
        FE6DB5
       -FDB1D8
        ======
         86F17D
        -FE0297
         ======
          F34CF0
         -F3FB2A
          ======
            1E72

base: 16
letters: 0123456789ABCDEF
difficulty: hard