[error] DEADLOCK/NODUP: no remaining values
[error] DEADLOCK/NODUP: no remaining values
        ????????
      +---------
518B9 | B9812732
       -1A9B20
        ======
         495693
        -288559
         ======
          396242
         -846706
          ======
          ??????

base: 12
letters: 0123456789AB
difficulty: medium