foo.cc: In function 'int main()':
foo.cc:30:6: warning: unused variable 't' [-Wunused-variable]
  int t;
      ^
foo.cc:29:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
foo.cc:35:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d", &edges[i][j]);
    ~~~~~^~~~~~~~~~~~~~~~~~~~

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