foo.cc: In function 'int main()':
foo.cc:3:14: error: 'ios' has not been declared
    3 | int main() { ios::sync_with_stdio(false); cin.tie(nullptr);
      |              ^~~
foo.cc:3:43: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    3 | int main() { ios::sync_with_stdio(false); cin.tie(nullptr);
      |                                           ^~~
      |                                           std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:146,
                 from foo.cc:1:
/usr/include/c++/13/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
foo.cc:10:5: error: 'll' was not declared in this scope
   10 |     ll max1 = LLONG_MIN, max2 = LLONG_MIN;
      |     ^~
foo.cc:12:11: error: expected ';' before 'x'
   12 |         ll x;
      |           ^~
      |           ;
foo.cc:13:16: error: 'x' was not declared in this scope
   13 |         cin >> x;
      |                ^
foo.cc:14:17: error: 'max1' was not declared in this scope
   14 |         if (x > max1) {
      |                 ^~~~
foo.cc:15:13: error: 'max2' was not declared in this scope
   15 |             max2 = max1;
      |             ^~~~
foo.cc:17:24: error: 'max2' was not declared in this scope
   17 |         } else if (x > max2) {
      |                        ^~~~
foo.cc:22:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   22 |     cout << (max1 - max2) << "\n";
      |     ^~~~
      |     std::cout
/usr/include/c++/13/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
foo.cc:22:14: error: 'max1' was not declared in this scope
   22 |     cout << (max1 - max2) << "\n";
      |              ^~~~
foo.cc:22:21: error: 'max2' was not declared in this scope
   22 |     cout << (max1 - max2) << "\n";
      |                     ^~~~