/in/foo.cc: In function 'int main()':
/in/foo.cc:5:115: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    5 |     std::cin>>t;for(int i=1;i<=t;i++){std::cin>>p[i];std::cout<<(p[i]>20)?std::to_string(p[i]):(p[i]>10)?"L":"R"<<endl;}
      |                                                                                                                   ^~~~
      |                                                                                                                   std::endl
In file included from /usr/include/c++/12/istream:39,
                 from /usr/include/c++/12/sstream:38,
                 from /usr/include/c++/12/complex:45,
                 from /usr/include/c++/12/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/12/bits/stdc++.h:54,
                 from /in/foo.cc:1:
/usr/include/c++/12/ostream:688:5: note: 'std::endl' declared here
  688 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~