#include <iostream>

#include <cmath>

using namespace std;

​

int main() {

  const double PI = 3.141592653589793;

  cout << tan(3) << "\n";

  cout << tan(-3) << "\n";

  cout << tan(0) << "\n";

  cout << tan(PI) << "\n";

  cout << tan(PI / 2.0) << "\n";

  return 0;

}

​