[error] DEADLOCK/NODUP: no remaining values
          7B04
     +--------
CD7B | 1448606
      -E02D
       ====
       C8C16
      -CAEEC
       =====
        C1500
       -C8AB0
        =====
          BC36
         -1B89
          ====
          C7E2

base: 15
letters: 0123456789ABCDE
difficulty: medium