[error] DEADLOCK/NODUP: no remaining values
        ????????
      +---------
8BB38 | 58775961
       -B088C
        =====
        885549
       -80B2A9
        ======
         809C06
        -80B2A9
         ======
           56011
          -5B59B
           =====
           ?????

base: 13
letters: 0123456789ABC
difficulty: medium