foo.cc: In function 'int main()':
foo.cc:28:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |                 for (int i = 1; i < m.second.size(); i++)
      |                                 ~~^~~~~~~~~~~~~~~~~
foo.cc:34:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |                 for (int i = 1; i < m.second.size(); i++)
      |                                 ~~^~~~~~~~~~~~~~~~~

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