/in/foo.cc: In function 'void has(std::__cxx11::string)':
/in/foo.cc:9:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<st.size();i++)
              ~^~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:24:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<s.size();i++)
               ~^~~~~~~~~
/in/foo.cc:28:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0;i<=h[t].size();i++)
                ~^~~~~~~~~~~~~