foo.cc: In function 'int main()':
foo.cc:4:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    4 |     cin>>m;
      |     ^~~
      |     std::cin
In file included from foo.cc:1:
/usr/include/c++/9/iostream:60:18: note: 'std::cin' declared here
   60 |   extern istream cin;  /// Linked to standard input
      |                  ^~~
foo.cc:8:17: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    8 |                 cout<<i<<" "<<j<<endl;
      |                 ^~~~
      |                 std::cout
In file included from foo.cc:1:
/usr/include/c++/9/iostream:61:18: note: 'std::cout' declared here
   61 |   extern ostream cout;  /// Linked to standard output
      |                  ^~~~
foo.cc:8:34: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    8 |                 cout<<i<<" "<<j<<endl;
      |                                  ^~~~
      |                                  std::endl
In file included from /usr/include/c++/9/iostream:39,
                 from foo.cc:1:
/usr/include/c++/9/ostream:599:5: note: 'std::endl' declared here
  599 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~

[Hydro](https://hydro.ac)提供评测服务