/in/foo.cc: In function 'int main()':
/in/foo.cc:4:5: error: 'ios' has not been declared
     ios::sync_with_stdio(0);
     ^~~
/in/foo.cc:5:5: error: 'cin' was not declared in this scope
     cin.tie(0);
     ^~~
/in/foo.cc:5:5: note: suggested alternative:
In file included from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:75:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/iostream:60:18: note:   'std::cin'
   extern istream cin;  /// Linked to standard input
                  ^~~
/in/foo.cc:6:5: error: 'cout' was not declared in this scope
     cout.tie(0);
     ^~~~
/in/foo.cc:6:5: note: suggested alternative:
In file included from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:75:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^~~~