foo.cc: In function 'int main()':
foo.cc:27:35: error: missing template arguments before '(' token
   27 |     sort(v.begin(),v.end(),greater());
      |                                   ^
foo.cc:28:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, std::__cxx11::basic_string<char> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |     for(int i = 0; i<v.size(); i++)
      |                    ~^~~~~~~~~

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