/in/foo.cc: In function 'int main()':
/in/foo.cc:19:28: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::__cxx11::basic_string<char>::size_type {aka long unsigned int}' [-Wformat=]
   printf("%d\n",s.find(b)+1);
                            ^