foo.cc: In function 'int main()':
foo.cc:9:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |  for(int i=0;i<s.size();i++)
      |              ~^~~~~~~~~
foo.cc:7:11: warning: variable 'xb' set but not used [-Wunused-but-set-variable]
    7 |  int max1,xb;
      |           ^~

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