#include <iostream>

#include <cmath>

using namespace std;

​

int main() {

  cout << asin(0.64) << "\n";

  cout << asin(-0.4) << "\n";

  cout << asin(0) << "\n";

  cout << asin(1) << "\n";

  cout << asin(-1) << "\n";

  cout << asin(2) << "\n";

  return 0;

}

​