foo.cc: In function 'int main()':
foo.cc:15:17: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   15 |     if(b.find(a)==-1)
      |        ~~~~~~~~~^~~~
foo.cc:22:26: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   22 |         while(b.find(a,n)!=-1)
      |               ~~~~~~~~~~~^~~~

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