foo.cc: In function 'int count_coloring(int, int, int)':
foo.cc:15:25: error: 'accumulate' was not declared in this scope
   15 |             dp[i][j] = (accumulate(dp[i-1].begin(), dp[i-1].end(), 0) - dp[i-1][j]) % p;
      |                         ^~~~~~~~~~

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