F5D2
      +---------
FC223 | 474E9EBA
       -FC223
        =====
        F0B1CE
       -FA0884
        ======
          C01DB
         -15EE1
          =====
          F96C1A
         -FE7FF8
          ======
           F99E7

base: 16
letters: 0123456789ABCDEF
difficulty: medium