public class UniquePairUser			// demonstrate the UniquePair class
{
	public static void main(String[] args)
	{
		UniquePair<Integer> apair=new UniquePair<>(new Integer(10), new Integer(20));	
		System.out.println(apair);			// shows the unique values
		apair.set1(new Integer(20));		// since the second item is already 20, this forces the second item to be null
		System.out.println(apair);			// demonstrate that the second item is null
	}
}