public class Square {
  // static int square(int x) { return x*x; }
  static double square(double d) { return d*d; }
  static String square(String st) { return "[" + st + "]"; }

  public static void main(String[] args) {
    System.out.println(square(4));
    System.out.println(square(2.4));
    System.out.println(square("Hello"));
  } // main (String)

} // Square