foo.cc:9:9: error: 'push_back' does not name a type
    9 | typedef push_back pb;
      |         ^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:26:13: error: 'class std::vector<long long int>' has no member named 'pb'
   26 |          ms.pb(tmp);
      |             ^~
foo.cc:44:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |        for(int i=op[tmp];i<ms.size();i++)
      |                          ~^~~~~~~~~~

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