class Mystery
{
  private int sum;
  
  public Mystery( int x )
  {
    sum = x;
  }
  
  public void increment( int inc )
  {
    sum = sum + inc;
  }
  
  public void increase( int sum )
  {
    sum++ ;
  }
  
  public String toString()
  {
    return ("sum: " + sum );
  }
}

public class Tester
{
  public static void main ( String[] args)
  {
    Mystery mystA = new Mystery( 10 );
    Mystery mystB = new Mystery( 20 );

    mystA.increment( 5 );
    mystB.increase( 3 );
    System.out.println("mystA " + mystA + " mystB " + mystB);
  } 
}