[error] DEADLOCK/NODUP: no remaining values
             78C
      +---------
02875 | 7631C08C
       -C05C32
        ======
         893898
        -608189
         ======
          C8646C
         -9043A7
          ======
           8A240

base: 13
letters: 0123456789ABC
difficulty: intermediate
restrictions: no multiplication
missing: B