public class Number {
  public double val;
  public Number(double d) {
    val = d;
  }
  static public Number op-(double d, Object c) { 
    return new Number(4);
  }
  static public double op-=(double d, Object c) { 
    return 7;
  }
  public Number op-(double d) { 
    return new Number(val - d);
  }
  public static void main(String[]args) {
  }
}