[error] DEADLOCK/NODUP: no remaining values
            883B
      +---------
6A980 | 2710B103
       -2C1C7
        =====
         7C001
        -2C1C7
         =====
         6C6140
        - 5C266
         ======
          6C3913
         -6C1628
          ======
            7238

base: 13
letters: 0123456789ABC
difficulty: medium