????????
      +---------
937EC | 9E01BEF8
       -937EC
        =====
         BDA5E
        -937EC
         =====
         DF94DF
        -DE2E5C
         ======
          6B0348
         -68847C
          ======
          ??????

base: 16
letters: 0123456789ABCDEF
difficulty: challenging