foo.cc: In function 'int main()':
foo.cc:3:5: error: 'cin' was not declared in this scope
    3 |     cin >> m >> n;
      |     ^~~
foo.cc:9:13: error: 'cout' was not declared in this scope
    9 |             cout << " ";
      |             ^~~~
foo.cc:12:13: error: 'cout' was not declared in this scope
   12 |             cout << "*";
      |             ^~~~
foo.cc:16:17: error: 'cout' was not declared in this scope
   16 |                 cout << " ";
      |                 ^~~~
foo.cc:19:17: error: 'cout' was not declared in this scope
   19 |                 cout << "*";
      |                 ^~~~
foo.cc:22:9: error: 'cout' was not declared in this scope
   22 |         cout << endl;
      |         ^~~~
foo.cc:22:17: error: 'endl' was not declared in this scope
   22 |         cout << endl;
      |                 ^~~~

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