[error] DEADLOCK/NODUP: no remaining values
       ????????
     +---------
4054 | 41021224
      -04301
       =====
        06152
       -32230
        =====
         61012
        - 4054
         =====
          05164
         -32230
          =====
          ?????

base: 7
letters: 0123456
difficulty: intermediate