/in/foo.cc: In function 'int main()':
/in/foo.cc:12:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~
/in/foo.cc:14:31: warning: 'wz' may be used uninitialized [-Wmaybe-uninitialized]
   14 |         string a=s.substr(0,wz);
      |                               ^
/in/foo.cc:9:30: note: 'wz' was declared here
    9 |         cin.tie(nullptr); ll wz,n=0;
      |                              ^~