foo.cc: In function 'int main()':
foo.cc:6:2: error: 'cin' was not declared in this scope
    6 |  cin>>a;
      |  ^~~
foo.cc:9:3: error: 'cout' was not declared in this scope
    9 |   cout<<"even";
      |   ^~~~
foo.cc:13:3: error: 'cout' was not declared in this scope
   13 |   cout<<"odd";
      |   ^~~~

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