text: #include <iostream>
  
  using namespace std;
  
  int main (int argc, char *argv[])
  {
    cout << "1" << endl;
    cout << "2" << endl;
    cout << "3" << endl;
    cout << "4" << endl;
    cout << "5" << endl;
    cout << "6" << endl;
    cout << "7" << endl;
    cout << "8" << endl;
    cout << "9" << endl;
    cout << "10" << endl;
    cout << "11" << endl;
    cout << "12" << endl;
    cout << "13" << endl;
    cout << "14" << endl;
    cout << "15" << endl;
    cout << "16" << endl;
    cout << "17" << endl;
    cout << "18" << endl;
    cout << "19" << endl;
    cout << "20" << endl;
    cout << "21" << endl;
    
    return 0;
  }
  