/in/foo.cc: In function 'int main()':
/in/foo.cc:5:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    5 |     cin>>n;
      |     ^~~
      |     std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/12/bits/stdc++.h:75,
                 from /in/foo.cc:1:
/usr/include/c++/12/iostream:60:18: note: 'std::cin' declared here
   60 |   extern istream cin;           /// Linked to standard input
      |                  ^~~
/in/foo.cc:6:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    6 |     cout<<pow(2,n);
      |     ^~~~
      |     std::cout
/usr/include/c++/12/iostream:61:18: note: 'std::cout' declared here
   61 |   extern ostream cout;          /// Linked to standard output
      |                  ^~~~