foo.cc: In function 'int main()':
foo.cc:30:11: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::set<int>::size_type' {aka 'long unsigned int'} [-Wformat=]
   30 |  printf("%d", s.size());
      |          ~^   ~~~~~~~~
      |           |         |
      |           int       std::set<int>::size_type {aka long unsigned int}
      |          %ld
foo.cc:25:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   25 |  scanf("%d%d", &n, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~
foo.cc:27:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   27 |   int x; scanf("%d", &x);
      |          ~~~~~^~~~~~~~~~

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