public class AvgTest
{
  public static void main(String[] args)
  {
    System.out.println(avg (10, 30, 20));
    System.out.println(avg(30,20));
  }
  
  public static double avg(double a, double b)
  {
    return ((a + b) / 2);
  }
    
  public static double avg(double a, double b, double c)
  {
    return ((a + b + c) / 3);
  }
}